Atomistic simulation of mechanical behavior and deformation mechanism in HfNbTaTiZr high entropy alloy: Influence of strain rate and temperature

High-entropy alloys (HEAs) represent a new class of structural materials offering exceptional mechanical strength, thermal stability, and corrosion resistance under extreme service conditions. Among them, body-centered cubic (BCC) refractory HEAs are particularly attractive but remain less understood compared to their FCC counterparts. This study aims to elucidate the mechanical response and deformation mechanisms of single-crystal HfNbTaTiZr HEA under varying thermal and loading conditions. Molecular dynamics (MD) simulations, based on a modified embedded atom method (MEAM) potential, were carried out under uniaxial tension at five temperatures (100–1200 K) and four strain rates (0.0005–0.01 ps -1 ). Stress–strain analysis revealed a maximum ultimate tensile strength (13.94 GPa) and Young’s modulus (180.14 GPa) at 100 K and the highest strain rate. Both properties decreased with temperature due to atomic softening but increased with strain rate as limited time for defect evolution enhanced strength. Adaptive common neighbor analysis (ACNA) showed that BCC-to-amorphous transformation is the primary deformation mechanism, while intrinsic stacking faults dominate at elevated temperatures and low strain rates. These results advance the understanding of temperature- and strain-rate-dependent behavior in refractory HEAs, offering guidance for the design of BCC HEAs with improved mechanical performance for high-temperature applications.