Effect of cooling rate during solidification of Aluminum - chromium alloy

Abstract

Controlling the distribution of alloying elements in aluminum casting and designing new processing practices are supported by an enhanced understanding of the thermodynamics and kinetics of solidification at industrial scales. While the behavior of eutectic forming elements such as copper has received a lot of attention, the interactions of peritectic-forming elements such as chromium is understudied. We herein use a time-dependent nucleation model for the calculation of the incubation time of nuclei in the liquid. This characteristic time is computed at various temperatures, and the results are presented in the form of a time-temperature diagram. Liquid phase thermodynamics of dilute compositions in the aluminum-chromium system are experimentally informed using the electrochemical potential difference method. Thermodynamic data obtained from these investigations are used to inform physical properties of the aluminum-chromium melt. The aforementioned time-temperature diagrams are recalculated using experimental data and theoretical cooling rates for phase selection are calculated. Critical cooling rates calculated from the model are applied to industrially relevant practices such as DC casting and Twin roll casting.