Effect of heat treatment on microstructure and tensile strength of NiCoCrAl alloy sheet fabricated by EB-PVD
(1. School of Aeronautics and Astronautics, Dalian University of Technology,
Dalian 116024, China;
2. Beijing Aeronautical Science and Technology Research Institute of COMAC,
Beijing 102211, China;
3. Center for Composite Materials, Harbin Institute of Technology, Harbin 150001, China)
Dalian 116024, China;
2. Beijing Aeronautical Science and Technology Research Institute of COMAC,
Beijing 102211, China;
3. Center for Composite Materials, Harbin Institute of Technology, Harbin 150001, China)
Abstract: The NiCoCrAl alloy sheet was fabricated by electron beam physical vapor deposition technique and the effects of the heat treatment on the microstructure and tensile strength of the NiCoCrAl alloy sheet were investigated. The heat treatment at 1050 °C is favorable to improve the interface bonding between the columnar structures due to the disappearance of the intergranular gaps. Comparing with the thin NiCoCrAl alloy sheet before heat treatment, the Ni3Al phase appears in the NiCoCrAl alloy sheet after heat treatment, which is favorable to improve the interface bonding between the columnar structures. The increase in the tensile strength and elongation is attributed to the improvement of the interface bonding between the columnar structures. The residual stress in the NiCoCrAl alloy sheet after heat treatment is reduced significantly, which also confirms that the interface bonding is improved by the heat treatment.
Key words: nickel-base alloys; heat treatment; microstructure; mechanical properties; physical vapor deposition