Journal
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
Volume 108, Issue -, Pages 270-280Publisher
JOURNAL MATER SCI TECHNOL
DOI: 10.1016/j.jmst.2021.07.042
Keywords
Medium-entropy alloy; Tensile property; Solid-solution strength; Strain-hardening rate; Stacking fault energy
Funding
- POSCO Science Fellowship of POSCO TJ Park Foundation
- National Research Foundation of Korea [NRF-2020R1C1C1003554]
- Creative Materials Discovery Program of the National Research Foundation of Korea (NRF) - Ministry of Science and ICT [NRF-2016M3D1A1023384]
- Korea Institute for Advancement of Technology (KIAT) - Korea Government (MOTIE) [P0 0 02019]
- German Research Foundation (Deutsche Forschungsgemeinschaft, DFG)
Ask authors/readers for more resources
High- and medium-entropy alloys with high solid-solution strength have significant effects on strain-hardening rate. In this study, the role of solid-solution strengthening on strain-hardening rate was revealed by controlling the Cr/V ratio in V1-xCrxCoNi alloys and investigating the evolution of deformation structures. The results showed that under the activated huge solid-solution strengthening effect, dislocation-mediated plasticity can be predominant over twinning, leading to an overall higher strain-hardening rate in the V-rich alloys.
High- and medium-entropy alloys (HEAs and MEAs) possess high solid-solution strength. Numerous investigations have been conducted on its impact on yield strength, however, there are limited reports regarding the relation between solid-solution strengthening and strain-hardening rate. In addition, no attempt has been made to account for the dislocation-mediated plasticity; most works focused on twinning- or transformation-induced plasticity (TWIP or TRIP). In this work we reveal the role of solidsolution strengthening on the strain-hardening rate via systematically investigating evolutions of deformation structures by controlling the Cr/V ratio in prototypical V 1- x Cr x CoNi alloys. Comparing the TWIP of CrCoNi with the dislocation slip of V 0.4 Cr 0.6 CoNi, the hardening rate of CrCoNi was superior to slip-band refinements of V 0.4 Cr 0.6 CoNi due to the dynamic Hall-Petch effect. However, as V content increased further to V 0.7 Cr 0.3 CoNi and VCoNi, their rate of slip-band refinement in V 0.7 Cr 0.3 CoNi and VCoNi with high solid-solution strength surpassed that of CrCoNi. Although it is generally accepted in conventional alloys that deformation twinning results in a higher strain-hardening rate than dislocation-mediated plasticity, we observed that the latter can be predominant in the former under an activated huge solid-solution strengthening effect. The high solid-solution strength lowered the cross-slip activation and consequently retarded the dislocation rearrangement rate, i.e., the dynamic recovery. This delay in the hardening rate decrease, therefore, increased the strain-hardening rate, results in an overall higher strain-hardening rate of V -rich alloys. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available