Influence of twinning thickness on the mechanical properties of crystalline-amorphous dual-phase CoCrFeNiMn high entropy alloy

Abstract

This study employs molecular dynamics simulation to investigate the influence of twin thickness on the mechanical properties and plastic deformation mechanisms for crystalline/amorphous dual-phase CoCrFeNiMn high-entropy alloy with varying amorphous layer thicknesses. The results revealed that for a minor amorphous layer thickness (d) of 1 nm, increasing the twin thickness (h) decreased average flow stress and peak stress within the models. It can be attributed to the fact that at smaller h, twin boundaries effectively hinder dislocation motion. However, as h increases, dislocation storage near twin boundaries and subsequent large-scale FCC→HCP phase transformation become more robust, reducing stress. On the other hand, when d thickness increases to 7 nm, stable average flow stress is observed due to thicker shear band formation during plastic deformation. Regardless of whether d was 1 nm or 7 nm, an increase in twin thickness augmented the likelihood of FCC→HCP phase transformation.