FCC to BCC transformation-induced plasticity based on thermodynamic phase stability in novel V10Cr10Fe45CoxNi35-x medium-entropy alloys
SCIE
SCOPUS
- Title
- FCC to BCC transformation-induced plasticity based on thermodynamic phase stability in novel V10Cr10Fe45CoxNi35-x medium-entropy alloys
- Authors
- JO, YONGHEE; CHOI, WON MI; KIM, DONGGEUN; ZARGARAN, ALIREZA; SOHN, SEOK SU; KIM, HYOUNG SEOP; LEE, BYEONG JOO; KIM, NACK JOON; LEE, SUNG HAK
- Date Issued
- 2019-01
- Publisher
- Nature Publishing Group
- Abstract
- We introduce a novel transformation-induced plasticity mechanism, i.e., a martensitic transformation from fcc phase to bcc phase, in medium-entropy alloys (MEAs). A VCrFeCoNi MEA system is designed by thermodynamic calculations in consideration of phase stability between bcc and fcc phases. The resultantly formed bcc martensite favorably contributes to the transformation-induced plasticity, thereby leading to a significant enhancement in both strength and ductility as well as strain hardening. We reveal the microstructural evolutions according to the Co-Ni balance and their contributions to a mechanical response. The Co-Ni balance plays a leading role in phase stability and consequently tunes the cryogenic-temperature strength-ductility balance. The main difference from recently-reported metastable high-entropy dual-phase alloys is the formation of bcc martensite as a daughter phase, which shows significant effects on strain hardening. The hcp phase in the present MEA mostly acts as a nucleation site for the bcc martensite. Our findings demonstrate that the fcc to bcc transformation can be an attractive route to a new MEA design strategy for improving cryogenic strength-ductility.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/99338
- DOI
- 10.1038/s41598-019-39570-y
- ISSN
- 2045-2322
- Article Type
- Article
- Citation
- Scientific Reports, vol. 9, no. 1, page. 2948, 2019-01
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