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Effect of Heat Treatment on the Microstructure and Fracture Behaviors of a Ni–Cr–Fe Superalloy
Author(s) -
Zhu Zhiyuan,
Chen Jiahuan,
Cai Yuanfei,
Li Jianqiang,
Shen Yang
Publication year - 2020
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201901070
Subject(s) - materials science , microstructure , microporous material , superalloy , carbide , transmission electron microscopy , fracture (geology) , phase (matter) , scanning electron microscope , metallurgy , composite material , solid solution , crystallography , nanotechnology , chemistry , organic chemistry
The influences of the size and shape of the γ′ phase and the type and distribution of carbides on the fracture behavior of a new Ni–Cr–Fe superalloy subjected to four different solution aging treatments are examined. The γ′ phase and γ matrix of the L1 2 ‐ordered structure maintain a coherent orientation relationship on the {100} and {110} atomic planes according to transmission electron microscopy observations. The material becomes stronger because the movement of dislocations is hindered by the γ′ phase and MC (Nb‐rich, Ti‐rich) and M 23 C 6 (Cr‐rich, Mo‐rich) carbides. The two‐stage aging system (850 °C × 4 h + 730 °C × 4 h) substantially increases the size of the γ′ phase. The solid solution sample shows a microporous‐aggregated ductile fracture, and the solution‐aged samples show a microporous‐aggregated crystalline fracture according to scanning electron microscopy observations. The fracture mechanism is also discussed.