Phase stability and mechanical property of γ′- (Ni1-xCox)3Al1-yCry alloys
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Published:2020-08-01
Issue:8
Volume:7
Page:086519
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ISSN:2053-1591
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Container-title:Materials Research Express
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language:
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Short-container-title:Mater. Res. Express
Author:
Wang YushuaiORCID,
Wu Xiaoxia,
Narsu B
Abstract
Abstract
The phase stability and mechanical property of γ′-(Ni1-xCox)3Al1-yCry phase of Ni-Co based superalloys are studied by the first-principles method. The calculated mixing enthalpies at 0 K indicate that the alloys are thermodynamically unstable against phase separation into Ni3AlCr and Co3AlCr alloys. Additions of 6.25 at % of Cr into (NiCo)3Al alloy can decrease the positive mixing enthalpy by 34%, hence Cr has a significant stabilizing effect on γ′ phase. The configurational entropy can further stabilize the alloy at finite temperature. A strong tetragonal shear softening is observed for (Ni1-xCox)3Al1-yCry alloys with large Co concentration. Cr additions could increase C′ of the alloys, and thus offset the softening effect of Co by a certain extent. The electronic density of states analysis demonstrates that the flexibility of Al p band and synergistic alloying effect are the physics behind the stabilization the γ′ phase of Ni-Co based superalloy by Cr alloying.
Funder
Natural Science Foundation of Inner Mongolia
National Natural Science Foundation of China
Subject
Metals and Alloys,Polymers and Plastics,Surfaces, Coatings and Films,Biomaterials,Electronic, Optical and Magnetic Materials
Cited by
1 articles.
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