A systematic study of interface properties for L12-Al3Sc/Al based on the first-principles calculation

Abstract

In current work, we used the first-principles to describe the structure stability, thermodynamic, strength, and electron properties, as well as unstable stacking fault energy, plasticity, and fracture behavior of low-index coherent interfaces (L12-Al3Sc(001)/Al(001), L12-Al3Sc(110)/Al(110), and L12-Al3Sc(111)/Al(111)). Results showed that the structure of the strongest interfaces of L12-Al3Sc(001)/Al(001), L12-Al3Sc(110)/Al(110), and L12-Al3Sc(111)/Al(111) were stacked similarly to bulk L12-Al3Sc or Al, as evidenced by the adhesion work (Wad) of 2.32, 2.53, and 1.91 J/m2, respectively. The calculated tensile stress in the rigid scheme is 15.30, 14.23, and 12.39 Gpa for L12-Al3Sc(001)/Al(001), L12-Al3Sc(110)/Al(110), and L12-Al3Sc(111)/Al(111) interfaces, respectively, whereas the corresponding tensile stress in the full-relaxed scheme is 10.65, 10.10 and 8.27 GPa, respectively. Furthermore, our findings revealed that the interfaces were prone to breaking on the Al side in the full-relaxed scheme, which is closer to reality. Moreover, the analysis of the partial density of states (PDOS) revealed the presence of s-p-d hybridization orbitals among the interfacial atoms. Finally, unstable stacking fault energy and Rice ratio indicated that the interfaces are plastic when subjected to shear stress in 〈100〉, 〈110〉, 〈−110〉, or 〈11−2〉 directions.

Keywords

• Interfacial strength
• Unstable stacking fault energy
• Plasticity
• Surface energy