Effects of chemical randomness on strength contributors and dislocation behaviors in a BCC multi-principal element alloy

Abstract

We conduct dislocation motion simulations in a body centered cubic TaCrVW multi-principal element alloy (MPEA) with different chemical randomness based on a newly developed machine learning potential. The critical stress is analyzed in terms of three contributions: (1) Peierls stress, (2) strengthening from the average antiphase boundary energy (APBE), and (3) strengthening due to the fluctuations of local APBE from the average value. With randomness increasing, the strength contribution due to the average APBE decreases, that from local APBE fluctuations increases, and the Peierls stress remains rather constant. The constancy of the Peierls stress and the opposite trends of the strengthening due to the average APBE and its fluctuations lead to rather invariant strengths of the TaCrVW alloy with different randomness. The present work elucidates the physical basis of strength in the studied TaCrVW alloy.