Non-monotonic interfacial solute drag imprints nanoscale chemical heterogeneity in rapidly solidifying alloys

A fundamental understanding of alloys’ microstructural development under far-from-equilibrium processing is crucial for predictive design of next-generation materials. Using non-equilibrium molecular dynamics simulations, we investigated solute partitioning and redistribution at liquid–solid (L-S) interfaces across a wide range of solidification velocities in binary alloys. We uncover a distinct parameter window at intermediate interface velocity, where solute is neither fully rejected nor completely trapped, producing peak Stokes–Einstein drag force that roughens the interface and imprints strong nanoscale heterogeneity of solute into solidified matrix. These findings provide a testable mechanism and practical lever to control nanoscale patterns in advanced manufactured materials.