High-throughput determination of interdiffusivity matrices in Ni-Al-Ti-Cr-Co-Mo-Ta-W multicomponent superalloys and their application in optimization of creep resistance

Abstract

The creep resistance of nickel-based superalloys at elevated temperature is inheritably correlated with interdiffusivity matrices, which are still difficult to be determined nowadays. In this work, the interdiffusion coefficient matrices of multicomponent nickel-based superalloys with seven alloying elements (i.e., Al, Ti, Cr, Co, Mo, Ta and W) at 1553 K were determined in a high-throughput way by employing the diffusion multiple technique and HitDIC software. The results showed that the main interdiffusion coefficients D∼AlAlNi and D∼WWNi over the investigated composition space were the highest and lowest, respectively. Moreover, it was found that Al + Ti is correlatedly accelerate the diffusion processes, while Mo + Ta + W has the tendency of decelerate the diffusion activities. Thereafter, the creep merit index of the concerned superalloys was evaluated using the measured interdiffusion coefficients, and the results showed the noticeable deviation from the experimental data in commercial superalloys. A great improvement can be then achieved by considering the effect of Re and Ru in the creep model. With the modified creep model, the composition of the superalloy with the optimal creep resistance can be finally chosen. It was proposed that increasing the contents of Ti, W and Mo to some extent may enhance the creep resistance of superalloys.