Mechanical behavior of a gradient short range order high-entropy alloy

Abstract

Gradient-structured materials have been widely studied in high-entropy alloys (HEAs) due to their unique properties; however, atomic ordering or compositional gradients associated with short-range order (SRO) effects have not yet been explored. The present study explores the mechanical response of the body-centered cubic HEA HfNbZrTaTi with different SRO configurations, including random distributions, weak SRO (wSRO), strong SRO (sSRO), and a gradient from random to sSRO samples, through molecular dynamics simulations. The results show that the SRO samples with gradients exhibited intermediate mechanical responses between sSRO and wSRO, suggesting a tunable behavior similar to multilayers. The gradient structure displays different mechanical properties assisted by twinning. Misorientation angles reveal that rotations are more dominant in sSRO than in weak or gradient structures. Significant local lattice rotations are associated with zones of higher Zr concentration, mainly following small B2 clusters. It is observed that twinning is promoted by the SRO anisotropy in the gradient sample, suggesting that inhomogeneities in HEAs can influence plastic deformation.