Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Imperfections in Recycled Aluminium-Silicon Cast Alloys
Jönköping University, School of Engineering, JTH. Research area Materials and manufacturing – Casting.
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

In striving to produce high quality cast components from recycled aluminium alloys,imperfections have to be considered, because recycled aluminium usually containsmore of it. However, there are great energy savings to be made by using recycledaluminium; as little as 5% of the energy needed for primary aluminium productionmay be required. High quality castings are dependent on, besides alloy chemistry, bothmelt quality and the casting process; the focus of this work is related to the meltquality.This thesis aims to increase knowledge about imperfections, foremost about Fe-richparticles, oxides/bifilms, and porosity. Experiments were performed at industrialfoundry facilities and in a laboratory environment. Melt quality was evaluated byproducing samples with the reduced pressure test (RPT), from which both densityindex (DI) and bifilm index (BI) could be measured, results that were related to tensiletest properties. Data from tensile test samples were analysed, and fracture surfacesand cross sections were studied in both light microscope and in scanning electronmicroscope (SEM). For the purpose of investigating nucleation of primary Fe-richparticles (sludge) differential scanning calorimetry (DSC) was used.In the analysis of results, a correlation between the morphology of particles and tensileproperties were found. And elongated Fe-rich β-particles were seen to fracturethrough cleavage towards the centre. However, DI and BI have not been possible torelate to tensile properties.The nucleation temperature of primary Fe-rich particles were found to increase withincreased Fe, Mn, and Cr contents, i.e. the sludge factor (SF), regardless of cooling rate.For a set SF, an increase of cooling rate will decrease the nucleation temperature.

Place, publisher, year, edition, pages
Jönköping: Jönköping University, School of Engineering , 2015. , 39 p.
Series
JTH Dissertation Series, 8
Keyword [en]
Imperfections, Recycled cast Al-Si alloy, Fe-rich particles, Melt quality, Fractography, Differential scanning calorimetry.
National Category
Metallurgy and Metallic Materials
Identifiers
URN: urn:nbn:se:hj:diva-26790ISBN: 978-91-87289-09-5 (print)OAI: oai:DiVA.org:hj-26790DiVA: diva2:814725
Presentation
2015-06-12, E1405, Jönköping University, School of Engineering, Jönköping, 10:00 (English)
Opponent
Supervisors
Available from: 2015-06-01 Created: 2015-05-28 Last updated: 2017-01-09Bibliographically approved
List of papers
1. On the complexity of the relationship between microstructure and tensile properties in cast aluminum
Open this publication in new window or tab >>On the complexity of the relationship between microstructure and tensile properties in cast aluminum
2015 (English)In: International Journal of Modern Physics B, ISSN 0217-9792, Vol. 29, no 10-11, 1540011Article in journal (Refereed) Published
Abstract [en]

The relationship between microstructure and mechanical properties in cast aluminium alloys is very complex. This relationship is also strongly affected by the casting process and melt handling. In the current study the mechanical properties were investigated and correlated with microstructural features such as porosity, Fe-rich particles, SDAS, Si-length. Process quality measures such as bifilm index, density index, and sludge factor were also investigated. The aim of the work was to understand the critical interactions between material microstructure and process quality in the development of high performance materials.

Keyword
imperfections, defects, porosity, fe-rich, sdas, silicon, bifilm, density, sludge, mechanical, properties, aluminium, aluminum
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-24687 (URN)10.1142/S0217979215400111 (DOI)000353523600012 ()2-s2.0-84928555789 (Scopus ID)
Conference
Asia Pacific Conference on Materials Processing 2014
Available from: 2014-12-23 Created: 2014-09-09 Last updated: 2017-12-05Bibliographically approved
2. Assessment of Quality when Delivering Molten Aluminium Alloys Instead of Ingots
Open this publication in new window or tab >>Assessment of Quality when Delivering Molten Aluminium Alloys Instead of Ingots
2013 (English)In: Light Metals Technology 2013 / [ed] Ian Stone, Brian McKay and Zhongyun Fan, 2013, Vol. 765, 266-270 p.Conference paper, Published paper (Refereed)
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-20256 (URN)978-3-03785-766-3 (ISBN)
Conference
the Sixth International Light Metals Technology Conference (LMT2013), July 24-26, 2013, Old Windsor, United Kingdom
Funder
Knowledge Foundation
Available from: 2013-01-17 Created: 2013-01-17 Last updated: 2017-08-21Bibliographically approved
3. On the formation of sludge intermetallic particles in secondary aluminium alloys
Open this publication in new window or tab >>On the formation of sludge intermetallic particles in secondary aluminium alloys
2015 (English)In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 46, no 8, 3713-3722 p.Article in journal (Refereed) Published
Abstract [en]

The primary precipitation of Fe-rich intermetallics in AlSi9Cu3(Fe) type alloys is studied for different Fe, Mn, and Cr contents and cooling rates. Differential scanning calorimetry, thermal analysis, and interrupted solidification with a rapid quenching technique were used in combination in order to assess the nucleation temperature of sludge particles, as well as to follow their evolution. The results revealed that the sludge nucleation temperature and the release of latent heat during sludge formation are functions of Fe, Mn, and Cr levels in the molten alloy (i.e., the sludge factor, SF) and cooling rate. Moreover, it can be concluded that sensitivity to sludge formation is not affected by cooling rate; i.e., a decrease in the SF will reduce sludge nucleation temperature to the same extent for a higher cooling rate as for a lower cooling rate. The sludge formation temperature detected will assist foundries in setting the optimal molten metal temperature for preventing sludge formation in holding furnaces and plunger systems.

Place, publisher, year, edition, pages
Springer, 2015
Keyword
aluminium alloys, sludge factor, Fe-rich intermetallics, DSC, thermal analysis
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:hj:diva-22716 (URN)2-s2.0-84932195555 ()
Available from: 2013-12-13 Created: 2013-12-13 Last updated: 2017-08-21Bibliographically approved

Open Access in DiVA

fulltext(7405 kB)820 downloads
File information
File name FULLTEXT01.pdfFile size 7405 kBChecksum SHA-512
65999dec5bab206f2ab79326545accd3c53fb3caabc1d5d2ac75f694b03b6bca013951e65d7804b2368f4f2c9911c7af2cb35e999d33695a12dd14248d1d6f96
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Bjurenstedt, Anton
By organisation
JTH. Research area Materials and manufacturing – Casting
Metallurgy and Metallic Materials

Search outside of DiVA

GoogleGoogle Scholar
Total: 820 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1715 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf