다이어프램 밸브용 Co계 초합금 냉간 압연재의 상온 인장 특성에 대한 강화 메커니즘 연구 (Strengthening Mechanism of Cold-Rolled Co-Based Super Alloy for Diaphragm Valves under Room Temperature Tensile Loading)

서지정보

· 발행기관 : 대한금속·재료학회
· 수록지 정보 : 대한금속·재료학회지 / 63권 / 5호 / 319 ~ 329페이지
· 저자명 : 박정현, 송노건, 최재호, 강두홍, 이기안

초록

Cold-rolled Co-Cr-Ni alloy (Elgiloy) and Co-Ni-Cr alloy (SPRON 510) can be considered fordiaphragm valve materials in gas valve systems. In this study, the effect of direct aging (DA) heat treatmenton the tensile properties of Co-based alloys was investigated and the influence of microstructural changes onthe tensile behavior was examined. The Co-Cr-Ni Elgiloy alloy exhibited a hexagonal close packed (HCP)phase formation through strain induced martensite transformation (SIMT) in both as-rolled and DAconditions, promoting finer grains due to increased sub-structured and recrystallized grains. In contrast, theCo-Ni-Cr SPRON 510 alloy showed a face centered cubic (FCC) single phase with a higher precipitates fractionand dislocation density. Both Co-based alloys showed improved hardness and strength after DA treatment,with the Co-Cr-Ni alloy demonstrating higher tensile strength and the Co-Ni-Cr alloy exhibiting higher yieldstrength and elongation. The Co-Cr-Ni alloy revealed fine shallow dimples and cleavage fracture mode, whileCo-Ni-Cr showed larger dimples and river patterns on tensile fracture surfaces. The Co-Cr-Ni alloy’sdeformation behavior was dominated by active SIMT due to low stacking fault energy (SFE), while the Co-Ni-Cr alloy primarily formed deformation twins due to higher SFE. The high tensile strength of the Co-Cr-Ni alloy was dominated by hardening effects due to a relatively fine grain size and SIMT behavior, while thehigh yield strength of the Co-Ni-Cr alloy was dominated by deformation twin, dislocation density, Taylor factorand high precipitate fraction.

영어초록

Cold-rolled Co-Cr-Ni alloy (Elgiloy) and Co-Ni-Cr alloy (SPRON 510) can be considered fordiaphragm valve materials in gas valve systems. In this study, the effect of direct aging (DA) heat treatmenton the tensile properties of Co-based alloys was investigated and the influence of microstructural changes onthe tensile behavior was examined. The Co-Cr-Ni Elgiloy alloy exhibited a hexagonal close packed (HCP)phase formation through strain induced martensite transformation (SIMT) in both as-rolled and DAconditions, promoting finer grains due to increased sub-structured and recrystallized grains. In contrast, theCo-Ni-Cr SPRON 510 alloy showed a face centered cubic (FCC) single phase with a higher precipitates fractionand dislocation density. Both Co-based alloys showed improved hardness and strength after DA treatment,with the Co-Cr-Ni alloy demonstrating higher tensile strength and the Co-Ni-Cr alloy exhibiting higher yieldstrength and elongation. The Co-Cr-Ni alloy revealed fine shallow dimples and cleavage fracture mode, whileCo-Ni-Cr showed larger dimples and river patterns on tensile fracture surfaces. The Co-Cr-Ni alloy’sdeformation behavior was dominated by active SIMT due to low stacking fault energy (SFE), while the Co-Ni-Cr alloy primarily formed deformation twins due to higher SFE. The high tensile strength of the Co-Cr-Ni alloy was dominated by hardening effects due to a relatively fine grain size and SIMT behavior, while thehigh yield strength of the Co-Ni-Cr alloy was dominated by deformation twin, dislocation density, Taylor factorand high precipitate fraction.

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