Effect of matrix dislocation strengthening on deformation-induced martensitic transformation behavior of metastable high-entropy alloys
Kenta Yamanaka, Manami Mori, Daishin Yokosuka, Kazuo Yoshida, Yusuke Onuki, Shigeo Sato, Akihiko Chiba
Abstract
In this study, we investigate the influence of dislocation strengthening in the metastable parent phase on the deformation-induced martensitic transformation behavior of a face-centered cubic (fcc) Co20Cr20Fe34Mn20Ni6 high-entropy alloy. Annealed and hot-swaged specimens were prepared. In-situ neutron diffraction experiments captured an accelerated transformation kinetics in the hot-swaged specimen due to accumulated dislocations. The phase-specific macrostress development showed that the hexagonal close-packed ε-martensite predominantly accommodated the macroscopic plastic deformation of the annealed counterpart. Conversely, the matrix dislocation strengthening promoted cooperative plasticity of the γ-matrix and the ε-martensitic phase, thus enhancing yield stress while preserving ductility.