Speakers

Understanding the core mechanisms of solid-solution strengthening in high-entropy materials (HEMs) requires isolating the effects of severe lattice distortion from intrinsic chemical complexity. This work investigates the influence of lattice distortion on dislocation mobility in face-centered cubic (FCC) alloys using large-scale molecular dynamics simulations, explicitly bridging the gap between traditional alloys and HEMs. By systematically comparing model systems—including binary Ni–W, ternary Fe–Ni–Cr, and the equiatomic CoCrFeMnNi Cantor alloy—we establish a unified kinetic description of dislocation glide across increasing levels of configurational entropy. Our results demonstrate that exacerbated chemical complexity in high-entropy systems leads to a pronounced increase in the critical resolved shear stress and a substantial reduction in dislocation velocity, directly reflecting enhanced lattice friction. Furthermore, detailed temperature-dependent analyses reveal a fundamental transition in the governing dislocation drag mechanism. While dislocation motion in pure metals (e.g., Ni) is dominated by phonon drag with a highly temperature-dependent drag coefficient, the severe lattice distortion inherent to multi-component systems progressively shifts the control to solute-induced lattice resistance. Consequently, the velocity–stress relations in HEAs exhibit markedly reduced temperature sensitivity. This study elucidates how lattice distortion and chemical disorder collectively suppress thermally activated dislocation motion, providing a coherent mechanistic framework for predicting strength–temperature relations in multi-principal element alloys. These insights offer quantitative guidelines for the design of next-generation high-entropy structural materials with exceptional mechanical performance.