| 고엔트로피 합금강의 시효경화 및 재결정 연화현상 |
| 최병학1, 장현수1, 김형섭2, 문종언2 |
1강릉원주대학교 신소재금속공학과
2포항공과대학교 신소재공학과 |
| Age Hardening and Re-crystallization Softening of a CoCrFeMnNi High Entropy Alloy |
| Byung Hak Choe1, Hyeon Su Jang1, Hyoung Seop Kim2, Jong Un Moon2 |
1Department of Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
2Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea |
| Correspondence |
Byung Hak Choe ,Tel: +82-33-640-2365, Email: cbh@gwnu.ac.kr
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Received: 13 March 2017; Accepted: 22 May 2017. Published online: 28 September 2017. |
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| ABSTRACT |
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Age hardening and re-crystallization softening of a type of high entropy alloy, CoCrFeMnNi, was performed to investigate the relationship between microstructure and the property of mechanical hardness. Equiatomic CoCrFeMnNi was produced by casting followed by homogenizing, cold rolling and post heat treatments. TEM analysis revealed that the microstructure of the as-rolled alloy was composed of elongated grains with twin laths and a shear band with fine grains, which exhibited a hardness of 371 HV. Following a 500℃ heat treatment the microstructure was composed of nano-twins and nano-grains, which represented age hardening, with 454 HV hardness. The microstructure of 700 ℃ heat treated samples was composed of re-crystallized grains and annealing twins, which represented annealed softening, with 244 HV hardness. The 700 ℃ heat treatment also produced spherical particles of 0.1 ㎛ maximum grain size, identified as Cr23C6 type carbide. |
| Keywords:
high entropy alloy, age hardening, annealed softening, TEM microstructure, nano-twin, nano-grain, Cr23C6 carbide |
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