Theoretical study of active Ca element on grain refining of carbon-inoculated Mg-Al alloy

Abstract

It is crucial to study grain refinement and refinement mechanism for promoting mechanical properties of Mg alloys. In this work, the influence mechanism of Ca on the grain refinement of Al2MgC2 and Al4C3 in Mg alloys was studied. It shows that Ca is easier to adsorb on the surfaces of Al2MgC2 and Al4C3 particles than Mg, which further promotes the adsorption Mg on the surfaces of Al2MgC2 and Al4C3 particles, leading to more crystal nuclei beyond the critical nucleation radius rK. The interface of Ca replaced Mg-2 is found to be more stable, for both Mg/Al2MgC2 interface and Mg/Al4C3 interface. We further revealed that Ca could effectively migrate from the first-layer to the second-layer in both the adsorption slabs and doped interface slabs under ambient condition.

Keywords

• First-principles calculation
• Heterogeneous nucleation
• Mg-Al alloy
• Critical nucleation radius
• Interfacial properties