Development of Co–Ni–Al–V–Ta–Cr-based superalloys with high-temperature strength and excellent oxidation resistance
Cuiping Wang, Youheng Chen, Haojun Zhuo, Wensu Cai, Yuechao Chen, Xiang Yu, Shuiyuan Yang, Yingju Li, Yuansheng Yang, Xingjun Liu
Abstract
In this study, the effects of V on the microstructure, lattice misfit, solvus temperatures, and oxidation behaviors of the Co–Ni–Al–V–Ta-based superalloys are investigated. The results show that all these alloys exhibit the γ’/γ two-phase structures. More importantly, the γ’ solvus temperature increases, and the oxidation resistance is significantly improved with the reduction of V concentration. Subsequently, the Ti (2 at.%) was added into Co–40Ni–10Al–4Ta–1V–12Cr alloy to further raise the properties of the superalloy. It is found that the Co–40Ni–10Al–4Ta–1V–12Cr–2Ti alloy exhibits a higher solvus temperature reaching 1200 °C of the γ′ phase, a low density of 8.48 g/cm3, a low lattice misfit of only +0.37 %, as well as exceptional oxidation resistance and mechanical properties.