An in situ synchrotron X-ray study of reverse austenitic transformation in a metastable FeMnCo alloy
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43578_2022_Article_818.pdf
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51c6eeb4e0c6928bbf7b1eb78e08f64d
Author(s)
Wei, Shaolou
Kang, Jiyun
Tasan, Cemal C.
Date Issued
November 29, 2022
Publisher
Springer International Publishing
Citation
Wei, Shaolou, Kang, Jiyun and Tasan, Cemal C. 2022. "An in situ synchrotron X-ray study of reverse austenitic transformation in a metastable FeMnCo alloy."
Version
Final published version
Abstract
Abstract
This study concerns reverse austenitic transformation of plastic strain-induced hexagonal close-packed martensite. With the aid of in situ synchrotron X-ray diffractometry, the kinetic features of the transformation and the defect content evolution in a metastable (Fe60Mn40)85Co15 alloy are quantitatively examined using 5, 20, and 100 °C/min heating rates. It is found that the reverse austenitic transformation can be activated below 200 °C and completes within a short time scale. Through a Kissinger-style kinetic analysis, the activation energy of the reverse austenitic transformation is determined as 171.38 kJ/mol, confirming its displacive nature. Although exponential attenuation is observed in both stacking fault probability and dislocation density upon the initiation of the transformation, the resulting microstructure (single-phase face-centered cubic structure) remains highly defected, exhibiting high Vickers hardness, but still preserving somewhat strain hardenability. Atomistic mechanisms for the reverse austenitic transformation are further conceived according to the crystallographic theory of martensitic transformation.
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MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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DOI of Published Version
https://doi.org/10.1557/s43578-022-00818-5
