Cryogenic-temperature fracture toughness analysis of non-equi-atomic V10Cr10Fe45Co20Ni15 high-entropy alloy
- Cryogenic-temperature fracture toughness analysis of non-equi-atomic V10Cr10Fe45Co20Ni15 high-entropy alloy
- Jo, Yong Hee; Doh, Kyung-Yeon; Kim, Dong Geun; Lee, Kwanho; Kim, Dae Woong; Sung, Hyokyung; Sohn, Seok Su; Lee, Donghwa; Kim, Hyoung Seop; Lee, Byeong-Joo; Lee, Sunghak
- Date Issued
- ELSEVIER SCIENCE SA
- Representative face-centered-cubic (FCC) high-entropy alloys (HEAs) or medium-entropy alloys (MEAs), e.g., equi-atomic CoCrFeMnNi or CrCoNi alloys, have drawn many attentions due to the excellent damage-tolerance at cryogenic temperature. The investigation of fracture toughness at 77 K is basically required for the reliable evaluation of high-performance alloys used for cryogenic applications; however, it has been rarely carried out for the non-equi-atomic FCC HEAs yet. In this study, tensile and fracture toughness tests were conducted on the non-equi-atomic V10Cr10Fe45Co20Ni15 alloy, and the results were compared with those of the equi-atomic CoCrFeMnNi and CrCoNi alloys. The present alloy shows a good damage tolerance at cryogenic temperature with tensile strength of 1 GPa and elongation of similar to 60%. The K-JIc fracture toughness values are 219 and 232 MPam(1/2) at 298 and 77 K, respectively, showing the increase in toughness with decreasing temperature. This increase results from the absence of twins at 298 K and the increased propensity to twin formation at 77 K, which is well confirmed by the variation of stacking fault energies (SFEs) by using Ab-initio calculations. The mechanical properties of the present alloy are actually similar or slightly lower than those of the other CoNiCr or FeMnCoNiCr alloy; instead, this study provides that neither composition nor certain elements are the most important factors dictating damage-tolerance of HEAs or MEAs. (C) 2019 Elsevier B.V. All rights reserved.
- Article Type
- JOURNAL OF ALLOYS AND COMPOUNDS, vol. 809, 2019-11
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