Microscopic observation of {gamma}-phase and {var_epsilon}- and {alpha}{prime}-martensite in Fe-Mn-Si-based shape memory alloys
- K. U. Leuven (Belgium). Dept. of Metallurgy and Materials Engineering
The martensitic transformation occurring in Fe-Mn-Si-based shape memory alloy has been studied by microstructural characterization and by a color etching method developed to reveal the martensite structure. With this technique, {gamma}-, {var_epsilon}-martensite and {alpha}{prime}-martensite can be easily distinguished and quantified. Two types of transformations, {gamma} {r_arrow} {var_epsilon} and {gamma} {r_arrow} {var_epsilon} {r_arrow} {alpha}{prime}, occur in the studied alloys. The {gamma} {r_arrow} {var_epsilon} transformation is observed in the specimen after annealing at high temperatures followed by air cooling to room temperature. Increasing annealing temperature enhanced the {gamma} {r_arrow} {var_epsilon}transformation during cooling. Both {gamma} {r_arrow} {var_epsilon} and {gamma} {r_arrow} {var_epsilon} {r_arrow} {alpha}{prime} transformations are found after applying a certain amount of deformation strain. Increasing the amount of applied strain induced the {gamma} {r_arrow} {var_epsilon} {r_arrow} {alpha}{prime} transformation more abundantly. The growth and intersection of {alpha}{prime}-martensite is enhanced when the applied strain is large. During reverse heating, {alpha}{prime}-martensite directly transformed back to {gamma} without reverting through {var_epsilon}-martensite.
- OSTI ID:
- 51679
- Journal Information:
- Materials Characterization, Journal Name: Materials Characterization Journal Issue: 2 Vol. 34; ISSN 1044-5803; ISSN MACHEX
- Country of Publication:
- United States
- Language:
- English
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