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

The microstructure, phase transformation temperature, gamma/gamma' 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 gamma' phase, resulting in a high gamma' solvus temperature (similar to 1131 degrees C) in the studied alloy. The gamma/gamma' lattice misfit of the 2Ta alloy was found to be similar to+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 degrees C), which is comparable to Co-12Ti-4Mo alloy. (c) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the microstructure, phase transformation temperature, lattice misfit, and mechanical properties of Co-4Ti-10V-2W-2Ta alloy. It was found that Ti, W, and Ta have a strong tendency to partition to the γ' phase, leading to a high γ' solvus temperature in the alloy. The alloy exhibited a low γ/γ' lattice misfit and excellent yield strength at high temperatures, comparable to Co-12Ti-4Mo alloy.