Probing the stability, adhesion strength, and fracture mechanism of Mg/Al2Y interfaces via first-principles calculations

Abstract

The interface is the “link bridge” between the reinforced phase and the matrix, and its microstructures and configurations will directly affect the overall performance of composites. In this work, the atomic configurations, electronic properties, interfacial stability, and adhesion strength of Mg(0001)/Al 2 Y(100) interfaces with Al and Y termination were studied using first-principles calculations. The current first-principles study results elucidated that the Al 2 Y(100)_Al surface has the most thermodynamically stability compared to other two surfaces with Al termination in the whole range of the yttrium chemical potential ( μ Y s l a b − μ Y b u l k , Δ μ Y ). Additionally, the Al 2 Y(100)_Y surface was less stable than the Al 2 Y(100)_Al surface when Δ μ Y < -0.64 eV; otherwise, Al 2 Y(100)_Y surface was more stable. Moreover, the Y-HCP configuration has the largest work of adhesion in all configurations of Mg(0001)/Al 2 Y(100) interface. Moreover, the interfacial energy of the Al-MT and Y-HCP configurations were 1.29~0.29 J/m 2 and 0.76~1.77 J/m 2 , respectively. Owing to the bonding strength between Y (Al) and Mg atoms near the interface, the tensile stress of the Mg(0001)/Al 2 Y(100) with Y-HCP (Al-MT) configuration has the largest value compared to other Y terminated (Al terminated) configurations, and the mechanical failure eventually occurs in the Mg (0001) slab. • The Al 2 Y (100) has the most thermodynamically stability compared to the others two low index surfaces. • The predicted critical tensile stress of Al-MT is approximately of 6.5 GPa. • The mechanical failure of Mg(0001)/Al 2 Y(100) interface eventually occurs in the Mg (0001) slab.