Multicomponent Co-Ti-based superalloy with high solvus temperature and low lattice misfit

Abstract The microstructure, phase transformation temperature, γ/γ′ lattice misfit, and mechanical properties of Co-4Ti-10V-2W-2Ta (at. %, referred to as 2Ta) quinary alloy were investigated in detail. In addition, the results show that Ti, W, and Ta exhibit a strong partitioning tendency to the γ′ phase, resulting in a high γ′ solvus temperature (~1131 °C) in the studied alloy. The γ/γ′ lattice misfit of the 2Ta alloy was found to be ~+0.33%, which is much lower than those of Co-Ti binary and Co-Ti-Mo/W/Re/Cr ternary alloys. Moreover, the designed alloy also exhibits excellent yield strength (880 MPa at 750 °C), which is comparable to Co-12Ti-4Mo alloy.