Far-from-equilibrium solid–liquid interfacial properties of aluminum

Simulating quantitatively far-from-equilibrium conditions, which is relevant to a host of rapid solidification processes, has remained a major challenge where theoretical models and physical mechanisms for far-from-equilibrium solid–liquid (SL) interface are essential. Herein, we investigate the effects of far-from-equilibrium state and external strain on SL interfacial properties by using capillary fluctuation method and models based on transition rate theory. Under an extreme temperature gradient (TG), both SL interfacial stiffness ( S ) and SL interface velocity ( v ) are found to increase with TG. The nonlinear relationship between v and temperature is revealed over a large undercooling range (640 K). It is found that an external strain ( ϵ ) of 1%–3% could decrease S by 10%–30%. v is found to increase with external strains at large undercooling. Tensile strains decrease the activation energy ( Q ) and viscosity, thus facilitating SL interface movement. A strain-dependent Gibbs–Thomson condition is proposed by incorporating linear S - ϵ and Q - ϵ relations. Our systematically theoretical discussion on the far-from-equilibrium SL interfacial properties could provide a predictive guideline on SL interface behavior in the additive or extreme manufacturing.