Atomistic simulation for the interaction between dislocation and solute atoms, clusters, and associated physical insights.

Solid-solution hardening (SSH), originated mainly from the point obstacles with prescribed resistance (short-range) or spherical inclusions with purely dilatational eigenstrain (long-range), is critical to materials science and technological applications. Dislocation gliding in solid-solution hardening alloys generally undergoes both short-range and long-range interactions. However, the respective contribution of each aspect remains unclear. Here, we successfully decouple the short-range lattice distortion and long-range size misfit of the solid-solution hardening effect by introducing two scaling factors (s1 and s3) and analyzing the contributions of each aspect on the solute/dislocation interaction, respectively. For scaling factor s1, the interaction energy is localized, resembling the short-range interactions without volume change. The scaling factor s3 is equivalent to a dilatation/constriction center with volume change. The interaction energy is a long-range parameter and well predicted from the pure continuum elasticity perspective. Large-scale molecular dynamics (MD) simulations reveal the unique impacts of two strengthening mechanisms on dislocations with different scaling factors. It is found that the energy landscape and size misfit effect of the solute atoms play important roles in the SSH effect. With deeply understanding the SSH effects and the rapidly increasing computational power, it may pave a practical way to apply MD simulations on complex strengthening mechanism studies. [ABSTRACT FROM AUTHOR]