A comprehensive study of the L12-Al3Nb/Al interface properties using first-principles calculations

Abstract

In this study, properties of low-index L12-Al3Nb/Al such as structure stability, thermodynamic, strength, electron properties, unstable stacking fault energy, plasticity, and fracture behavior of interface (L12-Al3Nb(001)/Al(001), L12-Al3Nb(110)/Al(110), and L12-Al3Nb(111)/Al(111)) were systematically studied. The results showed that the structure of the strongest interfaces of L12-Al3Nb(001)/Al(001), L12-Al3Nb(110)/Al(110), and L12-Al3Nb(111)/Al(111) were stacked similar to bulk L12-Al3Nb or Al, with maximum work of adhesion of 2.80 J/m2, 2.99 J/m2, and 1.74 J/m2, respectively. The maximum computed theoretical tensile strength of L12-Al3Nb (001)/Al(001), L12-Al3Nb (110)/Al(110), and L12-Al3Nb (111)/Al(111) interfaces were 18.71 GPa, 16.85 and 11.88Gpa respectively, for the rigid scheme; and 8.91 GPa, 8.52 GPa and 6.98 GPa respectively, for the full-relaxed scheme. Meanwhile, the interfaces were virtually prone to break on the Al side on full-relaxed stretching. Moreover, the partial density of states of the interface indicated that hybridization occurs among the Al-s, Al-p, Nb-s, Nb-p, and Nb-d orbitals, forming s-p-d hybrid orbital. Finally, based on the unstable stacking fault energy and Rice ratio, the interfaces have high plasticity once subjected to shear stress in the , , , or directions, which elucidate the interface properties and understand the underlying mechanism between L12-Al3Nb and Al alloys, thereby provide vital information to guide designing of novel Al alloys.

Keywords

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