Abstract
This study reports the formation of the ε-martensite phase induced by post-deformation annealing (PDA) after severe plastic deformation in the equiatomic CoCrNi medium-entropy alloy. This ε-martensite phase was identified by analyzing the microstructure and the magnetic properties. It was found that after three passes of equal-channel angular pressing (ECAP), annealing at 500 °C or 600 °C induces a clear ε-martensite phase without recrystallization, while upon increasing the annealing temperature to above the recrystallization temperature, i.e., 700 °C or 800 °C, the ε-martensite phase gradually disappears. In addition, the hardness and creep behavior during PDA were investigated via nanoindentation. A different creep behavior before and after recrystallization was observed. The possible formation mechanism of this martensitic transformation is discussed.
NSTL
Elsevier