TY - JOUR
T1 - Effect of Co element on microstructure and softening behavior of NiW medium heavy alloy
AU - Cao, Guoxin
AU - Dong, Jianxin
AU - He, Yongsheng
AU - Jiang, He
AU - Hao, Fang
AU - Nie, Zhihua
AU - Ma, Tengfei
AU - Fu, Baoquan
N1 - Publisher Copyright:
© 2025 Elsevier Ltd
PY - 2025/7
Y1 - 2025/7
N2 - In this study, a novel Ni-42W-XCo-1Mo medium heavy alloy (X = 0, 5, 10, 15, 20, wt%) was designed, and the impact of Co element on the microstructure and mechanical properties was investigated. The results indicated that the addition of Co effectively inhibited the formation of topologically close-packed (TCP) phases, which decreased with the addition of Co and reached a minimum in the Ni-42W-10Co-1Mo alloy. The yield strength of the Ni-42W-XCo-1Mo medium heavy alloy decreased with increasing Co content at both room temperature and high temperatures (750 °C). Specifically, the room-temperature yield strength of Ni-42W-1Mo alloy decreased from 516 MPa to 368 MPa after addition of 20 wt% Co, as well as the microhardness decreased from 271 HV to 233 HV. It was attributed to Co weakened precipitated strengthening effect and induced softening effect. Moreover, the Portevin-Le Chatelier (PLC) effect was observed in the Ni-42W-XCo-1Mo alloys during high temperature compression, which was attributed to the continuous dissolution and precipitation of the TCP phase repeatedly, leading to dislocation pinning and unpinning. Moreover, the Ni-42W-XCo-1Mo alloys showcased exceptional ductility, withstood up to 60 % strain without fracturing due to the face-centered cubic (FCC) matrix.
AB - In this study, a novel Ni-42W-XCo-1Mo medium heavy alloy (X = 0, 5, 10, 15, 20, wt%) was designed, and the impact of Co element on the microstructure and mechanical properties was investigated. The results indicated that the addition of Co effectively inhibited the formation of topologically close-packed (TCP) phases, which decreased with the addition of Co and reached a minimum in the Ni-42W-10Co-1Mo alloy. The yield strength of the Ni-42W-XCo-1Mo medium heavy alloy decreased with increasing Co content at both room temperature and high temperatures (750 °C). Specifically, the room-temperature yield strength of Ni-42W-1Mo alloy decreased from 516 MPa to 368 MPa after addition of 20 wt% Co, as well as the microhardness decreased from 271 HV to 233 HV. It was attributed to Co weakened precipitated strengthening effect and induced softening effect. Moreover, the Portevin-Le Chatelier (PLC) effect was observed in the Ni-42W-XCo-1Mo alloys during high temperature compression, which was attributed to the continuous dissolution and precipitation of the TCP phase repeatedly, leading to dislocation pinning and unpinning. Moreover, the Ni-42W-XCo-1Mo alloys showcased exceptional ductility, withstood up to 60 % strain without fracturing due to the face-centered cubic (FCC) matrix.
KW - Mechanical properties
KW - Medium heavy alloy
KW - Ni-based alloy
KW - Solidification microstructure
UR - http://www.scopus.com/inward/record.url?scp=105000987104&partnerID=8YFLogxK
U2 - 10.1016/j.intermet.2025.108759
DO - 10.1016/j.intermet.2025.108759
M3 - Article
AN - SCOPUS:105000987104
SN - 0966-9795
VL - 182
JO - Intermetallics
JF - Intermetallics
M1 - 108759
ER -