High-throughput evaluation of stress–strain relationships in Ni–Co–Cr ternary systems via indentation testing of diffusion couples
Kenta Goto, Ayako Ikeda, Toshio Osada, Ikumu Watanabe, Kyoko Kawagishi, Takahito Ohmura
Abstract
The experimental investigations of multi-component alloy systems require considerable time and effort in terms of sample preparation; in particular, when studying numerous material compositions, the melting, processing, and machining of each specimen at each composition are significantly time- and effort-intensive. To overcome this challenge, the high-throughput evaluation of the stress–strain curves associated with the chemical compositions and microstructures of a Ni–Co–Cr ternary system was performed by estimating the yield stress and tangent modulus via indentation testing. Four diffusion couples (involving the diffusion of Ni and Co) with different nominal Cr contents were prepared, and more than 570 stress-strain curves at the points with different chemical compositions and microstructures were measured. The addition of Cr solute increased the elastic modulus and hardness and decreased the normalized pile-up height, indicating a low strain hardening behavior. The estimated yield stress was strongly dependent on the Cr content, whereas the Co content did not sufficiently affect the strength. Moreover, the effects of crystal orientation on the indentation testing of the face-centered cubic and hexagonal close-packed phases are discussed. The proposed technique can facilitate the evaluation of elastoplastic behavior in multi-component systems in single phase (fcc), which can help achieve the statistical data-driven material development of Ni-based superalloys.