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  • 1.
    Adineh, Morteza
    et al.
    Shahid Bahonar Univ Kerman, Coll Engn, Dept Mat Engn & Met, Kerman 7618868366, Iran..
    Doostmohammadi, Hamid
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Shahid Bahonar Univ Kerman, Coll Engn, Dept Mat Engn & Met, Kerman 7618868366, Iran..
    Microstructure, mechanical properties and machinability of Cu-Zn-Mg and Cu-Zn-Sb brass alloys2019In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 35, no 12, p. 1504-1514Article in journal (Refereed)
    Abstract [en]

    Lead-free alloys have attracted great attentions recently due to the toxic nature of lead for the human body. In this study, low amounts of Mg and Sb were added to the Cu65-Zn35 brass and microstructure, mechanical properties and machinability of samples were compared to Cu65-Zn35 brass. Both Mg and Sb led to the promotion of beta ' phase as well as the formation of new ternary copper rich intermetallic particles. It was found that these particles had a significant role in the reduction of the ultimate tensile strength, toughness, work hardening and elongation while increasing the hardness of samples. Results of machinability evaluation of samples showed that the cutting forces were decreased significantly and morphology of chips were improved compared to Cu65-Zn35 brass sample.

  • 2.
    Andersson, Joel
    et al.
    University West, Department of Engineering Science, Division of Manufacturing Processes. Department of Materials Technology, GKN Aerospace Engine Systems, Trollhättan, Sweden och Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Sjöberg, G.
    Department of Materials Technology, GKN Aerospace Engine Systems, Trollhättan, Sweden och Department of Materials and Manufacturing Technology, Chalmers University of Technology, Gothenburg, Sweden.
    Viskari, L.
    Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden.
    Chaturvedi, M. C.
    Department of Mechanical and Industrial Engineering, University of Manitoba, Winnipeg, MB, Canada.
    Effect of Different Solution Heat Treatments on the Hot Ductility of Superalloys: Part 3 - Waspaloy2013In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 29, no 1, p. 43-53Article in journal (Refereed)
    Abstract [en]

    The susceptibility to heat affected zone cracking of Waspaloy has been investigated in terms of its hot ductility, measured as the reduction of area (RA). Gleeble testing with on-heating as well as on-cooling test cycles was carried out to illuminate the influence of different 4 h solution heat treatments between 996 and 1080°C. A ductility maximum of between 80 and 90%RA was found at 1050–1100°C for all conditions in the on-heating tests. Although the different heat treatment conditions showed similar macrohardness, the particle size and distribution of the γ′ and M23C6 phases differed, which significantly affected the on-heating ductility in the lower temperature test region. The ductile to brittle transition was initiated at 1100°C in the on-heating testing with indications of grain boundary liquation at the higher test temperatures. Ductility recovery, as measured in the on-cooling tests from 1240°C, was very limited with <30%RA for all conditions and test temperatures except for the 1080°C/4 h treatment, which exhibited 60%RA at 980°C.

  • 3. Andersson-Östling, Henrik C.M.
    et al.
    Seitisleam, Facredin
    Sandström, Rolf
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Technology.
    Influence of phosphorus, sulphur and grain size on creep in pure copper2009In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847Article in journal (Other academic)
    Abstract [en]

    Uniaxial creep tests have been performed at 175 °C to study the influence of phosphorus, sulphur and grain size on the creep properties of oxygen free copper. Copper with no phosphorous content and copper with 2000 μm grain size showed lower creep strength and ductility than the reference material which contained 58 ppm phosphorous and had 350 μm average grain size. Phosphorous content of 29 and 106 ppm showed no difference in relation to the reference material, and neither did grain sizes of 100 and 800 μm average grain size. 6 or 12 ppm sulphur did not affect the creep properties at all. The main creep rupture mechanisms were found to be cavitation and microcracking at the grain boundaries. The observed influence of P on creep is consistent to previously published models both with respect to creep rate and creep ductility.

  • 4. Andersson-Östling, Henrik C.M.
    et al.
    Seitisleam, Facredin
    Sandström, Rolf
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Testing and modelling of creep in copper friction stir welds2009In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847Article in journal (Other academic)
    Abstract [en]

    Specimens cut from friction stir welds in copper canisters for nuclear waste have been used for creep experiments at 75°C. The specimens were taken from a cross-weld position as well as heat affected zone and weld metal. The weld specimens exhibited shorter creep lives than the parent metal specimens by a factor of three in time. The cross weld and HAZ specimens were shorter by an order of magnitude when compared to the weld metal. The creep exponent was in the interval 50 to 69 implying that the material was well inside the power-law breakdown regime. The ductility properties expressed as reduction in area were not significantly different in the weld zones and all the rupture specimens demonstrated valu esexceeding 80%. The stationary creep rate for the parent metal was consistent with a previously developed model. The primary creep was successfully modelled. Weld reduction factors have been obtained by comparing the results from base metal tests and weld tests. Measured values at 75 °C for are about 6% for friction stir welds and 14% for electron beam welds.

  • 5.
    Bakshi, S. Das
    et al.
    Materials Science and Metallurgy, University of Cambridge.
    Leiro, Alejandro
    Prakash, Braham
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Bhadeshia, H.K.D.H.
    Materials Science and Metallurgy, University of Cambridge.
    Dry rolling/sliding wear of nanostructured pearlite2015In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 31, no 14, p. 1735-1744Article in journal (Refereed)
    Abstract [en]

    The dry rolling-sliding wear behaviour of pearlite that has an interlamellar spacing of just 85 nm has been characterised. Its wear resistance is found to be comparable to that of much harder bainitic steels. Microstructural observations indicate that there is substantial plastic deformation of both ferrite and cementite components of pearlite in the vicinity of the wear surface. Plasticity is not expected from Hertzian analysis that assumes a smooth contact surface. Instead, it is likely to be a consequence of exaggerated stresses due to surface roughness. The material remains ductile to shear strains in the order of 4. Diffraction data indicate that the coherent domain size is reduced to about half the interlamellar spacing and that some of the cementite may dissolve and contribute to the expansion of the lattice parameter of ferrite

  • 6.
    Bratberg, Johan
    et al.
    Thermo-Calc Software AB.
    Ågren, J.
    Royal Institute of Technology.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB.
    Diffusion simulations of MC and M7C3 carbide coarsening in bcc and fee matrix utilising new thermodynamic and kinetic description2008In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 24, no 6, p. 695-704Article in journal (Refereed)
    Abstract [en]

    A new thermodynamic database has been combined with an existing kinetic database to perform coarsening simulations in ternary systems including MC and M7C3 carbides in an fee matrix. The kinetic database was revised taking into consideration the new experimental information on the Fe-Cr-V-C system obtained in the present work, and available experiments on the ternary Fe-Cr-C and Fe-V-C systems. After revision the agreement between experimental results and simulations was satisfactory. It was found that the interfacial energy of M7C3 was twice as large as that of the MC carbide. The calculations for commercial steels with 6 alloy elements gave results in satisfactory agreement with new experimental measurements. The present coarsening simulations use the calculated equilibrium state and the observed particle sizes as the state for the start of the simulations. All the simulations were performed with the DICTRA software. © 2008 Institute of Materials, Minerals and Mining.

  • 7.
    Bratberg, Johan
    et al.
    Thermo-Calc Software AB, Stockholm Technology Park.
    Ågren, John
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Frisk, Karin
    Swerea KIMAB.
    Diffusion simulations of MC and M7C3 carbide coarsening in bcc and fcc matrix utilising new thermodynamic and kinetic description2008In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 24, no 6, p. 695-704Article in journal (Refereed)
    Abstract [en]

    A new thermodynamic database has been combined with an existing kinetic database to perform coarsening simulations in ternary systems including MC and M7C3 carbides in an fcc matrix. The kinetic database was revised taking into consideration the new experimental information on the Fe-Cr-V-C system obtained in the present work, and available experiments on the ternary Fe-Cr-C and Fe-V-C systems. After revision the agreement between experimental results and simulations was satisfactory. It was found that the interfacial energy of M7C3 was twice as large as that of the MC carbide. The calculations for commercial steels with 6 alloy elements gave results in satisfactory agreement with new experimental measurements. The present coarsening simulations use the calculated equilibrium state and the observed particle sizes as the state for the start of the simulations. All the simulations were performed with the DICTRA software.

  • 8.
    Chen, Kaixuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Univ Sci & Technol Beijing, Sch Mat Sci & Engn, Beijing 100083, Peoples R China.
    Chen, Xiaohua
    Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing, Peoples R China..
    Wang, Zidong
    Univ Sci & Technol Beijing, Sch Mat Sci & Engn, Beijing 100083, Peoples R China..
    Precipitates-interaction capture of nano-sized iron-rich precipitates during copper solidification2019In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847Article in journal (Refereed)
    Abstract [en]

    Nano-sized iron-rich precipitates reinforced copper alloys achieve excellent mechanical properties. Capture mechanism of iron-rich precipitates into copper grains during solidification was described but needs further validation. Here, Cu-1.5Fe-0.5Co (wt-%) alloy is fabricated by gravity casting. Iron-rich precipitates in nano and submicron scale (mostly < 100 nm) are well dispersed in copper grain interior. Traditional pushing/engulfment transition (PET) models are used to interpret the capture process of iron-rich precipitates during copper solidification, but all fail to match the experimental results. The precipitates-interaction capture mechanism is most reasonable for describing the capture process.

  • 9.
    Claesson, Erik
    et al.
    RISE, Swerea, KIMAB.
    Rod, Olivier
    RISE, Swerea, KIMAB.
    The effect of alloying elements on the corrosion resistance of brass2016In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 32, no 17, p. 1794-1803Article in journal (Refereed)
    Abstract [en]

    A systematic study has been performed on the effect of alloying elements arsenic (As), antimony (Sb) and phosphorus (P) on the dezincification resistance of α-phase in brass. The result showed that P formed particles with Al and Fe already at relatively high temperatures, leaving no P in solid solution and thus no protection against dezincification. Arsenic only formed particles at lower temperatures and offers a satisfactory protecting. However, with increasing As levels grain boundary attack was observed. Samples alloyed with Sb show a satisfactory resistance to dezincification and no grain boundary attack. Finally, a combination of As and Sb at low alloying levels provided an excellent dezincification resistance for brass containing typical impurity levels. This paper is part of a Themed Issue on Brass Alloys. © 2016 Swerea KIMAB.

  • 10. Cong, DY
    et al.
    Wang, YD
    Zetterstrom, P
    Peng, Ru
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Engineering Materials .
    Delaplane, R
    Zhao, X
    Zuo, L
    Crystal structures and textures of hot forged Ni48Mn30Ga22 alloy investigated by neutron diffraction technique2005In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 21, no 12, p. 1412-1416Article in journal (Refereed)
    Abstract [en]

    A ferromagnetic shape memory alloy of Ni48Mn30Ga22 prepared by induction melting was successfully hot forged. Strong textures and a large anisotropy of in plane plastic flow were developed during the hot forging process. The crystal structures, both in austenitic and martensitic states, were investigated by means of neutron powder diffraction technique. The result suggests that Ni48Mn30Ga22 has a cubic L2(1) Heusler structure at room temperature, the same as that in the stoichiometric Ni2MnGa. When cooled to 243 K, the Ni48Mn30Ga22 alloy changes into a seven layered orthorhombic martensitic structure. No substantial change of the neutron diffraction pattern was observed upon further cooling to 19 K, indicating that there is no intermartensitic transformation in the investigated alloy, which is different from the transformation processes in the Ni-Mn-Ga alloys with higher martensitic transformation temperatures.

  • 11. DAS, D.K.
    et al.
    Singh, Vakil
    Joshi, Shrikant V.
    High temperature oxidation behaviour of directionally solidified nickel base superalloy CM–247LC2003In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 19, no 6, p. 695-708Article in journal (Refereed)
    Abstract [en]

    The present paper describes the isothermal and cyclic oxidation behaviour of the technologically important nickel base directionally solidified superalloy CM-247LC in air in the temperature range 1000-1200°C. This superalloy behaves as a transition nickel base alloy under isothermal oxidation conditions and exhibits a fairly long transient oxidation period (~20 h at 1100°C). Irrespective of the temperature of exposure and nature of oxidation (isothermal or cyclic), a composite oxide scale develops on CM-247LC. While the outer portion of the oxide scale consists of either spinel (NiAl2O4) or a mixture of spinel and NiO, depending on oxidation temperature, the inner portion is always constituted of alumina. Beyond the transient period, the alloy is found to follow parabolic oxidation kinetics. The oxide layer that forms is invariably very non-uniform in thickness, and is dispersed with two types of oxide particles. While tantalum rich oxide particles are found scattered in the outer zone of the oxide layer, hafnium rich oxide particles lie close to the oxide/metal interface. Results also reveal that the nature of oxidation associated with the CM-247LC superalloy causes entrapment of metal islands in the oxide layer.

  • 12.
    Das, Yadunandan B.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Open Univ, Mat Engn, Walton Hall, Milton Keynes MK7 6AA, Bucks, England.
    Forsey, Alexander N.
    Open Univ, Mat Engn, Walton Hall, Milton Keynes MK7 6AA, Bucks, England..
    Kelleher, Joe
    Rutherford Appleton Lab, ISIS Facil, Didcot, Oxon, England..
    Kabra, Saurabh
    Rutherford Appleton Lab, ISIS Facil, Didcot, Oxon, England..
    Fitzpatrick, Michael E.
    Coventry Univ, Fac Engn & Comp, Coventry, W Midlands, England..
    Simm, Thomas H.
    Swansea Univ, Coll Engn, Bay Campus, Swansea, W Glam, Wales..
    Gungor, Salih
    Open Univ, Mat Engn, Walton Hall, Milton Keynes MK7 6AA, Bucks, England..
    Moat, Richard J.
    Open Univ, Mat Engn, Walton Hall, Milton Keynes MK7 6AA, Bucks, England..
    The influence of temperature on deformation-induced martensitic transformation in 301 stainless steel2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 17, p. 2114-2125Article in journal (Refereed)
    Abstract [en]

    Deformation-induced martensitic transformations are increasingly being used to create desirable mechanical properties in steels. Here, the kinetics of the deformation-induced martensitic transformation is investigated at 300, 263, 223, 173 and 100 K using in situ neutron diffraction during tensile loading. The results from these experiments show a distinct change in the transformation behaviour between 300 K and the tests conducted at 263 K and below, causing a difference in martensite structure. The difference in transformation kinetics is correlated to the suppression of slip at low temperatures, as evidenced using diffraction peak intensity analysis for different grain families and corroborated using transmission electron microscopy. A direct correlation between the deformation-induced martensite fraction and the work-hardening rate is shown.

  • 13.
    Forouzan, Farnoosh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Borasi, Luciano
    Luleå University of Technology.
    Vuorinen, Esa
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mücklich, Frank
    University of Saarland .
    Process Control Maps to Design an Ultra-High Strength-Ductile Steel2019In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 35, no 10, p. 1173-1184Article in journal (Refereed)
  • 14.
    Fredriksson, Hasse
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Haddad-Sabzevar, M.
    Hansson, K.
    Kron, J.
    Theory of hot crack formation2005In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 21, no 5, p. 521-529Article in journal (Refereed)
    Abstract [en]

    The hot crack sensitivity in metals is suggested to be caused by the supersaturation of vacancies created during the solidification process. Equations have been derived to predict the nucleation and growth of cracks by the condensation of vacancies. The transition temperature from brittle to ductile fracture was found to be related to the decrease in the supersaturation of vacancies due to an annealing process. The hot crack sensitivity was observed to be related to the supersaturation of vacancies, the diffusion rate, and the structure coarseness. The effect of surface active elements such as phosphorous and sulphur in steel alloys is discussed.

  • 15.
    Frisk, Karin
    RISE, Swerea, Swerea KIMAB.
    Simulation of precipitation of secondary carbides in hot work tool steels2012In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 28, no 3, p. 288-294Article in journal (Refereed)
    Abstract [en]

    Precipitation of secondary carbides in hot work tool steels during tempering heat treatments has been investigated using simulations based on a thermodynamic description coupled with kinetic parameters through multicomponent nucleation and growth models. The simulations reproduce the measured effects of steel composition on the precipitation of secondary carbides. Both Si and V increase the volume fraction of fine secondary carbides precipitated during tempering provided that the austenitising temperature is adjusted to give the same fraction of retained primary carbides. The most important effect of Si in 5%Cr steels is its influence on the primary carbide stability at austenitisation temperatures, but increasing the V contents has a strong effect on the fraction of secondary carbides, without increasing the size, and can thus improve the yield strength. The most critical input to the calculations is the thermodynamic description of the individual phases. © 2012 Institute of Materials, Minerals and Mining.

  • 16.
    Garcia-Mateo, Carlos
    et al.
    National Centre for Metallurgical Research (CENIM-CSIC), Department of Physical Metallurgy, Madrid, Spain.
    Sourmail, Thomas
    Ascometal-CREAS (Research Centre) Metallurgy, Hagondange cedex, France.
    Caballero, Francisca García
    Department of Physical Metallurgy, National Centre for Metallurgical Research (CENIM-CSIC), Madrid, Spain.
    Smanio, Véronique
    Ascometal-CREAS (Research Centre) Metallurgy, Hagondange cedex, France.
    Kuntz, Matthias
    Robert Bosch GmbH, Materials and Process Engineering, Stuttgart, Germany.
    Ziegler, C.
    ALD Vacuum Technology GmbH, Hanau, Germany.
    Leiro, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Vuorinen, Esa
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Elvira, Roberto
    Gerdau IzD, S. A. Barrio Ugarte, Basauri, Spain.
    Teeri, T.
    Metso Minerals Oy, Tampere, Finland.
    Nanostructured steel industrialisation: Plausible reality2014In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 30, no 9, p. 1071-1078Article in journal (Refereed)
    Abstract [en]

    It is not the first time that a consortium of steel makers, end users and scientists end up with unique approaches and developments in the physical metallurgy of steels. The present paper reveals the scientific and technological developments of a consortium sharing a common intrigue and interest for a unique microstructure, nanostructured bainite. Also known as low temperature bainite, its unique properties rely solely on the scale of the miscrostructure obtained by heat treatment at low temperature (150-350°C). Careful design based on phase transformation theory, some well known metallurgy facts and the necessary industrial experience were the ingredients for a further step towards the industrialisation of these microstructures.

  • 17. Heydarian, Abtin
    et al.
    Sajjadi, Seyed Abdolkarim
    Kern, Frank
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Characteristics evaluation of SiC/Si nanocomposites produced by spark plasma sintering2019In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 35, no 10, p. 1204-1211Article in journal (Refereed)
    Abstract [en]

    SiC-Si composites are widely used either as a bulk material or as a matrix for fibre reinforced ceramics. In the current research, nanocomposites of SiC-Si with different volume fractions of Si were sintered by spark plasma sintering (SPS) for the first time. The effect of Si content and different sintering parameters on relative density, microstructure, hardness and fracture toughness of the sintered materials have been investigated. The relative density increased from about 83 to 99% by increasing the sintering temperature to 1700 degrees C, sintering time to 10 min, and pressure to 70 MPa for composites containing >20 vol.-% Si. The results revealed that the full dense SiC-20 vol.-%Si composite can be obtained by SPS at 1700 degrees C, 10 min and 70 MPa. Moreover, in this condition, the hardness and toughness of the composites reached the optimum values.

  • 18.
    Hulme-Smith, Christopher
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing. Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England..
    Ooi, S. W.
    Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England..
    Bhadeshia, H. K. D. H.
    Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England..
    Intermetallic-strengthened nanocrystalline bainitic steel2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 16, p. 1976-1979Article in journal (Refereed)
    Abstract [en]

    A new thermally stable, nanocrystalline bainitic steel has been developed, rich in nickel and aluminium. During tempering, it is expected that a significant quantity of intermetallic precipitates will form. This was confirmed by X-ray diffractometry, scanning transmission electron microscopy, Fourier transform analysis of atomic column images, energy dispersive X-ray spectroscopy and selected area electron diffraction. These are the first intermetallics to be produced in a nanocrystalline bainitic steel.

  • 19.
    Hulme-Smith, Christopher
    et al.
    Materials Science and Metallurgy, University of Cambridge, UK.
    Peet, Mathew James
    Materials Science and Metallurgy, University of Cambridge, UK.
    Lonardelli, I.
    Materials Engineering and Industrial Technologies, University of Trento, Italy.
    Dippel, Ann Christin
    Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
    Bhadeshia, Harshad Kumar Dharamshi Hansraj
    Materials Science and Metallurgy, University of Cambridge, UK.
    Further evidence of tetragonality in bainitic ferrite2015In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 31, no 2, p. 254-256Article in journal (Refereed)
    Abstract [en]

    There is growing evidence that bainitic ferrite which retains a substantial amount of carbon in solid solution does not have cubic symmetry. We provide additional data on a different nanostructured bainitic steel to support this evidence, based on synchrotron X-ray diffraction experiments. The data are consistent only with a displacive transformation mechanism for bainite.

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  • 20.
    Hutchinson, Bevek
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Komenda, Jacek
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Observations of dynamic transformation products in a commercially hot-rolled steel2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 10, p. 1197-1200Article in journal (Refereed)
    Abstract [en]

    Sufficient evidence has now accumulated to show that dynamic transformation (DT) is a real phenomenon in steels and can take place over a wide range of temperatures in the austenite regime. During plastic deformation, some of the austenite is transformed to ferrite despite austenite being the chemically more stable equilibrium phase. Occurrence of DT has been demonstrated in various laboratory tests but apparently not in commercially hot-rolled steels. In this note, we review some old results on high strength low alloy strip steel that contained microstructural features that appear to have been caused by DT. We deduce that DT occurred early in the rolling schedule, leading to thin-pancaked sheets of ferrite in the final product. The presence of these pre-existing ferrite nuclei frequently gave rise to adjacent regions of coarse polygonal ferrite grains during cooling.

  • 21.
    Hutchinson, Bevek
    et al.
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, KIMAB.
    Martin, David
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, KIMAB.
    Karlsson, Oskar
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, KIMAB.
    Lindberg, Fredrik
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, KIMAB.
    Thoors, Håkan
    RISE - Research Institutes of Sweden (2017-2019), Materials and Production, KIMAB.
    Marceau, Ross K.W.
    Deakin University, Australia.
    Taylor, Adam S.
    Deakin University, Australia.
    Vanadium microalloying for ultra-high strength steel sheet treated by hot-dip metallising2017In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 33, no 4, p. 497-506Article in journal (Refereed)
    Abstract [en]

    Ultra-high strength steel sheets have been subjected to heat treatments that simulate the thermal cycles in hot-dip galvanising and galvannealing processes and evaluated with respect to their resulting mechanical properties and microstructures. The steels contained suitable contents of carbon (∼0.2%), manganese (1.2%) and chromium (0.4%) to ensure that they could be fully transformed to martensite after austenitisation followed by rapid cooling in a continuous annealing line, prior to galvanising. Different contents of vanadium (0–0.1%) and nitrogen (0.002–0.012%) were used to investigate the possible role of these microalloying elements on the strength of the tempered martensite. Vanadium, especially when in combination with a raised nitrogen content, helps to resist the effect of tempering so that a larger proportion of the initial strengthening is preserved after the galvanising cycle, giving tensile strength levels exceeding 1000 MPa. Different deoxidation practices using aluminium or silicon have also been included. These showed similar strength levels at corresponding carbon contents but the bendability of the Si-killed steel sheet was considerably superior. Microstructural examinations have been made on the annealed steels but the reason for the beneficial effect of vanadium is still not fully explained. It is concluded that microalloying with vanadium is a very promising approach in the development of corrosion-resistant ultra-high strength steel sheet products.

  • 22.
    Hutchinson, Bevis
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Critical assessment 16: Anisotropy in metals2015In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 31, no 12, p. 1393-1401Article in journal (Refereed)
    Abstract [en]

    Sources of anisotropy in metals are discusssed as well as ways of interpreting and modelling this behaviour. A number of case studies are presented relating to mechanical and magnetic properties.

  • 23.
    Ion, John
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Easterling, Kenneth E.
    Luleå tekniska universitet.
    Computer modelling of weld-implant testing1985In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 1, no 5, p. 405-411Article in journal (Refereed)
    Abstract [en]

    A theoretical model is developed for determining the optimum notch position in an implant test used for predicting the susceptibility to hydrogen cracking during welding. Using a microcomputer for processing the equations for weld-bead geometry and heat flow during welding, a microstructural cross-section, with the notch positioned at the center of the grain-growth zone, and an implant testing diagram, showing the notch position and microstructure as a function of welding parameters, can be generated. A single bead-on-plate weld is used to determine the unknown kinetic and geometrical constants in the equations. It is shown that notch position is very sensitive to the type of welding process employed and that implant diagrams thus can be used to position the notch with greater reliability and hence reduce the scatter in the fracture loads measured in this test

  • 24. Ion, John
    et al.
    Moisio, T.
    Lappeenranta University of Technology.
    Paju, M.
    Lappeenranta University of Technology.
    Johansson, J.
    Lappeenranta University of Technology.
    Laser transformation hardening of low alloy hypoeutectoid steel1992In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 8, no 9, p. 799-803Article in journal (Refereed)
    Abstract [en]

    The principles of laser transformation hardening were investigated using a low alloy special steel having a microstructure of pearlite and proeutectoid ferrite. Temperature fields and phase transformations were modelled. Particular attention was paid to increases of the Ac1 and Ac3 transformation temperatures owing to the rapid thermal cycles produced by laser heating. Dissolution of proeutectoid ferrite is shown to control the formation of a homogeneous hardened case. Experimental data are in good agreement with the predictions of the model. A diagram was constructed which describes the case geometry and microstructure in terms of the process variables and is an aid to optimising practical processing parameters. The models are flexible and may be used for laser transformation hardening of other ferrous alloys having inhomogeneous microstructures.

  • 25.
    Jaradeh, Majed
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Carlberg, Torbjörn
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Analysis of solidification in a Bridgman furnace as a simulation of DC casting of aluminium alloy slabs2007In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 23, no 4, p. 475-482Article in journal (Refereed)
    Abstract [en]

    A vertical Bridgman directional solidification equipment has been used in several investigations to simulate DC casting of wrought aluminium alloys. As a base for such investigations and alloy developments, it is important to have an understanding of the performance of the used furnace during simulation of casting conditions. In this investigation the thermal conditions in the furnace have been analysed in detail, both by measurements and by mathematical modelling. The thermal characteristics of the furnace, such as gradient, growth rates and cooling rates have been compared to conditions in large ingots. The DC casting conditions, which the simulations have been compared to, are casting of slabs of 330 and 600 mm width of an AA3003 type alloy. The results show that the experiments are able to simulate the cooling conditions in the ingots except from the surface zone. Comparisons of the microstructure have been made and a good agreement has been obtained for structure parameters such as grain size and DAS.

  • 26.
    Jarfors, A. E. W.
    Royal Institute of Technology, KTH, Department of Materials Processing, Stockholm, Sweden.
    Peritecticlike precipitation of titanium carbide in Al-Ti-C melts at 1373 K1999In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 15, no 5, p. 481-494Article in journal (Refereed)
    Abstract [en]

    The reaction between an Al-Ti melt and a carbon containing medium, i.e. pure graphite or molten aluminium containing aluminium carbide, was studied. Experiments were carried out at 1373 K, using three different experimental setups. Depending on the carbon source, titanium carbide precipitated as a layer or as free particles. Classical nucleation theory for homogeneous and heterogeneous nucleation is used to assess the surface tension. The influence of stoichiometry on surface tension and nucleation is discussed. The formation of a continuous layer, or peritecticlike precipitation of titanium carbide, is theoretically analysed. The growth of the layer is rate controlled by the mass transfer of carbon at the interface, plausibly as a result of the ordering tendencies in titanium carbide. The degeneration of precipitation into that of freely formed particles is found to be nucleation controlled. A model for degenerate precipitation is proposed, including predictions of the reaction front compositions, growth rate, and particle fractions in a dilute ternary system. The model is in good agreement with experiments, after compensating for settling of the precipitates, except in predicting the precipitated fractions. © 1999 IoM Communications Ltd.

  • 27.
    Jarfors, A. E. W.
    Department of Materials Processing, Royal Institute of Technology, Stockholm, Sweden.
    Solubility of copper in titanium carbide1996In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 12, no 12, p. 990-994Article in journal (Refereed)
    Abstract [en]

    The solubility of copper in titanium carbide (TiCx) was studied experimentally. The solubility was assessed in two different ways: (a) titanium carbide was added to a copper-titanium melt, (b) titanium carbides formed in situ, from graphite and titanium, were analysed. The stoichiometries were implicitly assessed. The solubility of copper in titanium carbide was found to decrease with increasing carbon content. This behaviour was compared to the solubility of chromium in titanium carbide, which increases in solubility with increasing carbon content. The role of vacancies in the solution is briefly discussed. © 1996 The Institute of Materials.

  • 28.
    Kumara, Chamara
    et al.
    Univ West, Sweden.
    Deng, Dunyong
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering.
    Moverare, Johan
    Linköping University, Department of Management and Engineering, Engineering Materials. Linköping University, Faculty of Science & Engineering. Univ West, Sweden.
    Nylen, Per
    Univ West, Sweden.
    Modelling of anisotropic elastic properties in alloy 718 built by electron beam melting2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 5, p. 529-537Article in journal (Refereed)
    Abstract [en]

    Owing to the inherent nature of the process, typically material produced via electron beam melting (EBM) has a columnar microstructure. As a result of that, the material will have anisotropic mechanical properties. In this work, anisotropic elastic properties of EBM built Alloy 718 samples at room temperature were investigated by using experiments and modelling work. Electron backscatter diffraction data from the sample microstructure was used to predict the Youngs modulus. The results showed that the model developed in the finite element software OOF2 was able to capture the anisotropy in the Youngs modulus. The samples showed transversely isotropic elastic properties having lowest Youngs modulus along build direction. In addition to that, complete transversely isotropic stiffness tensor of the sample was also calculated.

  • 29.
    Kumara, Chamara
    et al.
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Deng, Dunyong
    Linköping University, Division of Engineering Materials, Department of Management and Engineering, Linköping, Sweden.
    Moverare, Johan
    Linköping University, Division of Engineering Materials, Department of Management and Engineering, Linköping, Sweden.
    Nylén, Per
    University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Modelling of anisotropic elastic properties in alloy 718 built by electron beam melting2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 5, p. 529-537Article in journal (Refereed)
    Abstract [en]

    Owing to the inherent nature of the process, typically material produced via electron beam melting (EBM) has a columnar microstructure. As a result of that, the material will have anisotropic mechanical properties. In this work, anisotropic elastic properties of EBM built Alloy 718 samples at room temperature were investigated by using experiments and modelling work. Electron backscatter diffraction data from the sample microstructure was used to predict the Young’s modulus. The results showed that the model developed in the finite element software OOF2 was able to capture the anisotropy in the Young’s modulus. The samples showed transversely isotropic elastic properties having lowest Young’s modulus along build direction. In addition to that, complete transversely isotropic stiffness tensor of the sample was also calculated. © 2018 Institute of Materials, Minerals and Mining.

  • 30. Li, Yan
    et al.
    Huyan, Fei
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Physical Metallurgy.
    Ding, Wei
    Microstructure and tensile properties of a 0.20C-4.86Mn steel after short intercritical-annealing times2019In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 35, no 2, p. 220-230Article in journal (Refereed)
    Abstract [en]

    This work studies the microstructure and tensile properties of a cold-rolled Fe-0.20C-4.86Mn (mass %) steel after short intercritical annealing (IA) times using scanning and transmission electron microscopy, and uniaxial tensile tests. The short IA time is applied to represent the process characteristics of the industrial continuous annealing line. The experimental results show that IA temperature has a strong influence on the final microstructure and tensile properties while IA time has less. The fractions of retained austenite are much higher after IA at 650 and 675 degrees C than the other IA temperatures, and thus improving elongation. Simulations using the DICTRA software and constitutive modelling are further performed to assist the understanding of the microstructure evolution and stress-strain curves.

  • 31. Liu, Xihe
    et al.
    Zhao, Congcong
    Zhou, Xin
    Eibl, Florian
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Tsinghua University, People’s Republic of China.
    Liu, Wei
    Meiners, Wilhelm
    CNT-reinforced AlSi10Mg composite by selective laser melting: microstructural and mechanical properties2019In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 35, no 9, p. 1038-1045Article in journal (Refereed)
    Abstract [en]

    Carbon nanotube (CNT)-AlSi10Mg composites were fabricated by selective laser melting (SLM). The influence of CNTs on the density, microstructure, and strength of SLM CNT-AlSi10Mg composites was investigated. The addition of CNTs over 0.1 wt-% significantly damaged the density due to the high surface energy of the CNTs. The network Si eutectic had no significant difference in either the SLM AlSi10Mg alloy or the CNT-AlSi10Mg composite. Reserved CNTs with a short scale were observed in the SLM CNT(0.5 wt-%)-AlSi10Mg composite. The ultimate tensile strength of the 0.05 wt-% CNT-AlSi10Mg composite was 441.2 +/- 0.9 MPa, which was higher than that of AlSi10Mg alloy. The grain boundary strengthening played an important role in the reinforcement of CNT-AlSi10Mg composite because of the refined grain.

  • 32. Markaki, A. E.
    et al.
    Öhman, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Porter, A. E.
    Biomaterial characterisation2015In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 31, no 2, p. 129-130Article in journal (Refereed)
  • 33.
    Moverare, Johan
    Materials Technology, Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Thermal-Mechanical Fatigue Behavior of CMSX-4 in Virgin and Long Term aged Condition2007In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 23, no 12, p. 1450-1453Article in journal (Refereed)
    Abstract [en]

    The thermal–mechanical fatigue (TMF) behaviour of the single crystal alloy CMSX-4 has been investigated under out of phase (OP) loading in the 100–1000°C temperature range with a dwell period of 5 min. The material was tested in both virgin and aged conditions. Even though aging at 1000°C for 4000 h seems to have no significant influence on the OP TMF life, a more ductile fracture appearance was generally found for the aged material. This is also illustrated by the difference in the shape of the stabilised stress–strain hysteresis loop between virgin and aged materials, where one can see a higher degree of inelastic deformation for the aged material due to a higher degree of creep relaxation during the dwell period and more plastic deformation in the cold end of the TMF cycle. Microstructure studies showed that rafting occurred in the virgin material even during a short term TMF test with a maximum temperature of 1000°C, which may explain some of the similarities in terms of cyclic life between the two tested material conditions. The rafting was however more pronounced in the aged material where topologically close-packed phases also were found.

  • 34.
    Navara, E.
    et al.
    Luleå tekniska universitet.
    Li, C.-H.
    Center for Solid State Science, Arizona State University.
    Smith, D.J.
    Center for Solid State Science, Arizona State University.
    Investigation of microstructural changes occurring during warm working of manganese partitioned dual phase steel1990In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 6, no 2, p. 151-155Article in journal (Refereed)
    Abstract [en]

    This paper presents results from studies using transmission and high resolution electron microscopy of as-received and warm worked manganese partitioned dual phase steel. A growing manganese enriched austenite grain shares two different boundaries with ferrite: (a) a stationary coherent boundary, replacing a stretch of the original ferrite/ferrite boundary, and (b) a migrating non-coherent boundary. This finding gives support to a previously described mechanism of the nucleation and growth of the manganese enriched austenite. The structure of the warm worked steel consists of recovered ferrite strengthened by substructure, and fine martensitic lathes separated by low angle boundaries which resulted from the transformation of deformed non-recrystallised austenite grains

  • 35.
    Navara, Eric
    et al.
    Luleå tekniska universitet.
    Bengtsson, B.
    Luleå tekniska universitet.
    Easterling, Kenneth E.
    Luleå tekniska universitet.
    Austenite formation in manganese-partitioning dual-phase steel1986In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 12, no 2, p. 1196-1201Article in journal (Refereed)
    Abstract [en]

    Manganese-containing ferritic-pearlitic steels have been studied after intercritical annealing for various times at temperatures of 700 and 725 degree C, during which austenite formation occurred at ferrite grain boundaries. Light and electron optical microscopy, and scanning transmission electron microanalysis and microdiffraction were employed for the study, in which both microstructural development and manganese redistribution were examined in detail. It was observed that the formation of austenite is associated initially with a migration of ferrite grain boundaries. It is proposed that this boundary migration is induced by manganese diffusion along the boundaries, and that this in turn provides the mechanism for rapidly transporting manganese to the growing austenite. On this basis, we find that austenite formation in these steels is associated with manganese-rich migrated ferrite boundaries, and is not dependent on the presence of cementite particles for nucleation

  • 36. Olafsson, P.
    et al.
    Sandström, Rolf
    KTH, Superseded Departments, Materials Science and Engineering.
    Calculations of electrical resistivity for Al-Cuand Al-Mg-Sialloys2001In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 17, no 6, p. 655-662Article in journal (Refereed)
    Abstract [en]

    A system for thermodynamical calculations (Thermo-Calc) was used to derive the solid solubility of the alloying elements in commercial Al-Cu and Al-Mg-Si alloys. The electrical resistivity was then calculated using a model developed by the authors based on the Matthiessen's rule. The calculated resistivity agreed with the observed resistivity within +/-2.5 n Omegam for the Al-Mg-Si alloys and +/- 2n Omegam for the Al-Cu alloys, except for Al-Mg-Si alloys containing boron or chromium and AI-Cu alloys with special compositions. MST/3725.

  • 37. Ooi, S. W.
    et al.
    Ramjaun, T. I.
    Hulme-Smith, Christopher
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Morana, R.
    Drakopoulos, M.
    Bhadeshia, H. K. D. H.
    Designing steel to resist hydrogen embrittlement Part 2: precipitate characterisation2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 14, p. 1747-1758Article in journal (Refereed)
    Abstract [en]

    A novel, low-alloy steel has been designed for use in the oil and gas industry. Its high strength and hydrogen trapping potential are derived from a martensitic microstructure containing a dispersion of fine vanadium-molybdenum alloy carbides that evolve during tempering. In this second paper, the effect of quench rate from austenitisation and tempering conditions are investigated with respect to the microstructure. The alloy loses its tempering resistance following slow-cooling from austenitisation as a result of MC precipitation, leading to vanadium depletion and significant M2C coarsening. This is predicted using computer simulation and confirmed by high energy X-ray diffraction, combined with electron microscopy.

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  • 38.
    Pederson, Robert
    et al.
    Luleå tekniska universitet.
    Babushkin, Oleg
    Luleå tekniska universitet.
    Skystedt, F
    Volvo Aero Corporation, Materials Technology.
    Warren, Richard
    Luleå tekniska universitet.
    Use of high temperature X-ray diffractometry to study phase transitions and thermal expansion properties in Ti-6Al-4V2003In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 19, no 11, p. 1533-1538Article in journal (Refereed)
    Abstract [en]

    Phase transitions in Ti-6Al-4V were studied by means of high temperature X-ray diffraction using at resistance heated furnace in high vacuum and Cu Kα radiation. The α and β phases could, be opened conveniently using the (10.0), (00.2) and (10.1) peaks of the a structure and the (110) peak of the β. The phase composition of the specimen at selected times and temperatures was determined from spectra recorded in the range 32-45° (θ), the scan time being ≈ 8 min. The technique was successfully used to monitor the kinetics of the α-β transition during heating and the β-α transition during cooling, including the transformation kinetics during isothermal holds. Measurements of the interplanar distance change with temperature for the crystallographic planes of α and β phases enabled derivation of the overall thermal expansion for the alloy using a rule of mixtures

  • 39.
    Peng, Ru
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Engineering Materials.
    Rode, Nils
    Intitute of Materials Technolgy University of Kassel.
    Odén, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Mechanical Engineering, Engineering Materials.
    Gibmeier, Jens
    Institute of Materials Technology University of Kassel.
    Scholtes, B
    Institute of Materials Technology University of Kassel.
    Characterisation of residual stress distribution in clinching joints of carbon steel by diffraction methods2003In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 19, no 3, p. 336-342Article in journal (Refereed)
    Abstract [en]

    Sheet joints of carbon steel fabricated by two different clinching methods, namely TOX and Eckold, have been investigated. The holding force of the joints was determined by shear tension tests and the deformation microstructure was characterised using optical microscopy. The surface residual stress and mean residual stress distributions as a function of increasing distance from the outer diameter of the interlock button were mapped by X-ray and neutron diffractometry, respectively.The Eckold joints showed more severe joint distortion in the form of global sheet bending, but nevertheless possessed higher shear tension strength than the TOX joints. Characteristic residual stress distributions depending on the clinching method were found in both the TOX and Eckold joints. The observed residual stress distributions have been attributed to the different die construction employed by the two methods, which permitted different degrees of plastic deformation during clinching.

  • 40.
    Rajabi, Zahra
    et al.
    Shahid Bahonar Univ Kerman, Dept Met & Mat Sci, Jomhoori Eslami Blvd, Kerman, Iran..
    Doostmohammadi, Hamid
    Shahid Bahonar Univ Kerman, Dept Met & Mat Sci, Jomhoori Eslami Blvd, Kerman, Iran..
    Effect of addition of tin on the microstructure and machinability of alpha-brass2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 34, no 10, p. 1218-1227Article in journal (Refereed)
    Abstract [en]

    This study was aimed at developing lead-free brass alloys with the goal of substituting lead element with tin. For this purpose, lead-free alloys with tin were developed and the microstructure, hardness and machining behaviour of the Cu-30%Zn alloy was compared with Cu-30%Zn-x%Sn (x = 1.2, 3.2, 5.4, 8,11.4,13.9,17.4). The results showed that the addition of Sn to single-alpha phase brass led to the formation of duplex (alpha + beta') brass and then the formation of (beta' + gamma) brass both with increased hardness. In addition, the addition of Sn to Cu-30%Zn alloy led to the decrement of equivalent machining forces (F-m), surface roughness and also the promotion of chip fragmentation due to the formation of the beta' phase, which is an improvement in machinability.

  • 41. Ringer, S.P.
    et al.
    Kuziak, R.P.
    Easterling, K.E.
    Luleå tekniska universitet.
    Liquid film simulation of Zener grain boundary pinning by second phase particles1991In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 7, no 3, p. 193-200Article in journal (Refereed)
    Abstract [en]

    The geometry of the interaction of second phase particles with migrating grain boundaries has been studied using a liquid film simulation. The geometries observed show that the perimeter of intersection between boundary and particle can be complex, often not lying in a single plane through the particle. The curvature of the boundary when in contact with the particle is also complex, sometimes displaying double curvature and often of opposite sign. These observations have been used to modify previous calculations quantifying the grain boundary pinning effect. Measurements from the photographs of these interactions have been applied to a force equilibrium approach for calculating the pinning force and these results are found to be in good agreement with values obtained using an energy analysis based on grain boundary shape change

  • 42.
    Safi-Naqvi, S.H.
    et al.
    University of Birmimgham.
    Hutchinson, Bevis
    RISE, Swerea, Swerea KIMAB.
    Barnett, M.R.
    Deakin University.
    Texture and mechanical anisotropy in three extruded magnesium alloys2008In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 24, no 10, p. 1283-1292Article in journal (Refereed)
    Abstract [en]

    One ZM61 alloy (6·2%Zn, 1·2%Mn) and two magnesium alloys containing nominally 3% of neodymium and yttrium respectively have been prepared in the form of hot extruded flat strips. Their textures and microstructures have been quantified and series of mechanical tests were carried out to determine plane stress yield loci in both the solution treated and aged conditions. The ZM61 alloy had a sharp texture and marked anisotropy of strength that could be rationalised in terms of deformation by basal 〈a〉 slip and {101̄2}〈1011〉 twinning. This material was much weaker in compression than in tension. Precipitation hardening on aging caused a greater impedance to twinning than to slip with the result that the anisotropy was somewhat reduced. The Mg-3Nd alloy had a very weak and different texture but nevertheless demonstrated a pronounced anisotropy of strength. Aging increased the yield stress by about 80% and also inhibited twinning to some extent although the degree of anisotropy remained almost unaffected. The Mg-3Y alloy which showed a texture of intermediate strength was different in type from either of the others. Its strength behaviour was close to isotropic; in particular, no difference existed between tensile and compressive loading, and aging produced only a marginal increase in strength. Twins were relatively infrequent in the deformed Mg-3Y alloy but its mechanical behaviour could not be rationalised according to simple models. © 2008 Institute of Materials, Minerals and Mining.

  • 43.
    Smuk, Olena
    et al.
    KTH, Superseded Departments, Materials Science and Engineering.
    Hanninen, H
    Liimatainen, J
    Mechanical ana corrosion properities of P/M-HIP super duplex stainless steel after different industrial heat treatments as used for large components2004In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 20, no 5, p. 641-644Article in journal (Refereed)
    Abstract [en]

    Mechanical tensile and impact toughness tests and critical pitting corrosion temperature (CPT) tests were performed on samples of Duplok 27, a P/M-HIP duplex stainless steel containing copper, after heat treatments simulating industrial heat treatments of large components. It was shown that copper alloying has positive effects on mechanical tensile properties leading to hardening and more uniform deformation. No negative effects of copper alloying on corrosion resistance properties were found. A drastic drop in impact toughness values and CPT of samples cooled at controlled cooling rates is explained by the precipitation of intermetallic secondary phases or their precursors. Lower CPT of a NG-GTAW (narrow gap gas tungsten arc welding) welded joint is explained by the lower level of alloying than that of the base material. The high temperature region of precipitation of intermetallic secondary phases is shifted towards higher temperatures than assumed for Duplok 27 P/M-HIP duplex stainless steel.

  • 44.
    Solimanjad, N.
    et al.
    Luleå tekniska universitet.
    Larsson, Roland
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Machine Elements.
    Die wall friction and influence of some process parameters on friction in iron powder compaction2003In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 19, no 12, p. 1777-1782Article in journal (Refereed)
    Abstract [en]

    The coefficient of friction is a system response parameter, which is affected by a number of parameters such as normal load and sliding distance. Experimental results describing the influence of these parameters are presented in this study. These parameters have a crucial role in the modelling of the compaction process and also provide an in depth understanding of the mechanism of friction in powder compaction. The powder surface characteristics change continuously during the pressing, making friction measurement quite difficult. An attempt has been made to identify and separate the powder behaviour during compaction. The experimental results show that the plastic deformation of the surface in contact with the die wall occurs at an early stage of the compacting. At densities above 5 g cm3 the plastic deformation is completed and the variation of the coefficient of friction is minimal. It has been observed that most changes of the powder surface occur at low densities. The nature of the friction has also been discussed.

  • 45.
    Sourmail, Thomas
    et al.
    Ascometal-CREAS (Research Centre) Metallurgy, BP 70045, Hagondange cedex 57301.
    Caballero, Francisca García
    Department of Physical Metallurgy, National Centre for Metallurgical Research (CENIM-CSIC), Madrid.
    García-Mateo, Carlos
    Department of Physical Metallurgy, National Centre for Metallurgical Research (CENIM-CSIC), Madrid.
    Smanio, Véronique
    Ascometal-CREAS (Research Centre) Metallurgy, BP 70045, Hagondange cedex 57301.
    Ziegler, C.
    ALD Vacuum Technology GmbH, Wilhelm Rohn Str. 35, Hanau.
    Kuntz, Matthias
    Robert Bosch GmbH, Materials and Process Engineering, PO Box 300240, Stuttgart.
    Elvira, Roberto
    Gerdau IzD, S. A. Barrio Ugarte, Basauri.
    Leiro, Alejandro
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Vuorinen, Esa
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Teeri, T.
    Metso Minerals Oy, PO Box 237, Tampere.
    Evaluation of potential of high Si high C steel nanostructured bainite for wear and fatigue applications2013In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 29, no 10, p. 1166-1173Article in journal (Refereed)
    Abstract [en]

    The present study is concerned with the potential of high carbon, high silicon steel grades isothermally transformed to bainite at low temperature (

  • 46.
    Strid, J.
    et al.
    Luleå tekniska universitet.
    Porter, D.A.
    Luleå tekniska universitet.
    Easterling, Kenneth E.
    Luleå tekniska universitet.
    Microstructure and plasticity of An Al-Al/6Fe directionally solidified eutectic alloy1985In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 1, no 2, p. 161-166Article in journal (Refereed)
    Abstract [en]

    The microstructure and plasticity of a directionally solidified Al-Al//6Fe eutectic alloy was investigated using quantitative STEM-EDX microanalysis, in situ tensile testing in STEM/SEM, and light/electron optical studies of microstructure before and following drawing and extrusion to wire. It is found that in spite of the brittle nature of the aligned Al//6Fe rods, the alloy as a whole is relatively ductile and can even be drawn or extruded to wire. In the deformed condition the Al//6Fe rods are broken up and the fragmens distributed uniformly throughout the aluminum matrix. The tensile strength and ductility of these drawn wires are good, 400 MN m** minus **2 and 83% area reduction, respectively. Microanalysis studies show that the iron content of the aluminum matrix following solidification is 0. 04 at. %, corresponding to an undercooling of approx. 3 K below the eutectic temperature. The iron content of the matrix can be reduced further by precipitation treatments.

  • 47.
    Stålnacke, Emil
    et al.
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Claesson, Erik
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Obitz, Charlotta
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Lilja, Mirjam
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Odqvist, Joakim
    KTH Royal Institute of Technology, Sweden.
    Hagström, Johan
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Rod, Olivier
    RISE - Research Institutes of Sweden, Materials and Production, KIMAB.
    Corrosion–microstructure interrelations in new low-lead and lead-free brass alloys2018In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847Article in journal (Refereed)
    Abstract [en]

    Stress-relieving heat treatment has been reported to deplete the corrosion resistance of new low-lead and lead-free brass alloys. How the heat treatment, processing and material composition relates to the microstructure and corrosion performance is not well understood. The present study aims to fill this knowledge gap by mapping stress-relieving annealing conditions and different standardised compositions to their respective microstructures and dezincification performance. It was found that loss of corrosion resistance was only the most severe for alloys with higher aluminium and iron content. These alloys displayed significant precipitation of intermetallic aluminium arsenide particles on grain boundaries, twins and lead particles, as well as the formation of β-phase along grain boundaries. © Swerea KIMAB 2018

  • 48. Sun, Yufu
    et al.
    Lv, Yezhe
    Zhengzhou University, China.
    Zhang, Yan
    Zhao, Jingyu
    Wu, Yue
    Microstructural and properties evolution of austenitic heat resistant steel after addition of aluminium2013In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 29, no 5, p. 511-516Article in journal (Refereed)
    Abstract [en]

    Effect of aluminium on microstructure and properties of austenitic heat resistant steel was investigated. The results showed that Al addition led to formation of spheroidal and dispersed Ni3Al. After solution treatment, Ni3Al particles experienced a significant refinement from 1.5 mu m to nanoscale (similar to 80 nm). Matrix transformed from austenite to ferrite when addition of Al was >4.72%. Oxidation resistance of samples containing 4.72% Al was two times higher than Al free samples due to the formation of compacted Al2O3 scales. Excessive Al resulted in the formation of Al3Fe5O12 and AlN on oxidation surface, which destroyed the oxidation resistance. Dispersedly precipitated Ni3Al effectively supported the matrix and enhanced the wear resistance, and samples containing 4.72% Al performed similar to 80% higher in wear resistance than Al free samples. Al significantly improved the microstructure and the properties of austenitic heat resistant steel, and samples containing 4.72% Al performed the optimal combination properties.

  • 49. Svendsen, L
    et al.
    Jarfors, Anders
    Jönköping University, School of Engineering, JTH, Mechanical Engineering.
    Al-Ti-C phase diagram1993In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 9, no 11, p. 948-957Article in journal (Refereed)
    Abstract [en]

    Equilibrium experiments have been performed at 1373, 1173, and 973 K, with alloys of compositions within the aluminium rich corner of the Al–Ti–C phase diagram. The samples have been metallographically investigated using light optical microscopy and a scanning electron microscope equipped with a system for energy dispersive spectrometry. Equilibrium phases, as well as effects of cooling, have been identified. Dynamic effects originating from cooling are discussed and a tentative phase diagram is proposed. It was predicted theoretically and confirmed experimentally that a class II reaction involving four phases occurs, i.e. Al(l) + TiC(s)Al3Ti(s) + Al4C3(s), below 1100 K.

  • 50.
    Vishnu, P. Ravi
    et al.
    Luleå tekniska universitet.
    Li, W.B.
    Luleå tekniska universitet.
    Easterling, Kenneth E.
    Luleå tekniska universitet.
    Heat flow model for pulsed welding1991In: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 7, no 7, p. 649-659Article in journal (Refereed)
    Abstract [en]

    An analytical model of the heat flow during pulsed welding is constructed by first developing a solution for the temperature distribution due to an instantaneous, stationary, Gaussian heat source. This solution is first extended to treat the case of a moving heat source for a single pulse and then extended to treat the case of pulsed welding by summing the temperature changes due to a series of pulses. Test gas tungsten arc welds in mild steel are used to confirm the validity of the model.

12 1 - 50 of 56
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