Development of a pattern making method for strain measurement on microstructural level in ferritic cast iron
2014 (English)Conference paper (Refereed)
The current paper focuses on development of a method for studying micro-scale strains on the microstructure of ferritic cast iron. For this purpose, in-situ tensile tests were done under the optical microscope combined with digital image correlation (DIC). Critical in this development was to be able to achieve a reliable high spatial resolution of strain around microstructural features, such as graphite particles. Measurement of local strain fi elds in cast iron materials have so far been relying on displacement of naturally occurring microstructure patterns such as graphite particles, which limits the spatial resolution of strain measurement. In order to increase the spatial resolution of the measured strain, a pit etching procedure was applied to generate a random speckle pattern on the ferritic matrix. Th e critical challenges of in-situ investigation of microstructural deformation were identifi ed as speckle pattern quality and accurate selection of subset size and strain window size. Th e traceability of this method was studied by benchmarking the measured elastic modulus with that obtained from full-scale tensile test. Th e elastic modulus calculated from average strains, measured by DIC, showed a good agreement with material’s elastic modulus. Th is validates the measured localized strain values and can be used as a validation for modeling of local deformation.
Place, publisher, year, edition, pages
Ferritic cast iron, Digital image correlation (DIC), In-situ tensile test, Pit etching, Subset size, Strain window size
Metallurgy and Metallic Materials
IdentifiersURN: urn:nbn:se:hj:diva-28326OAI: oai:DiVA.org:hj-28326DiVA: diva2:871745
23rd International Conference on Processing and Fabrication of Advanced Materials (PFAM-XXIII), Roorkee, India, December 5-7, 2014