Chemical bonding, thermodynamic stability and mechanical strength of Ni₃Ti/α-Al₂O₃ interfaces by first-principles study

We performed a first-principles calculation to investigate the 85 different Ni₃Ti/Al₂O₃ interfaces. The study shows that the formation of metal-oxygen interfaces and high symmetric interfacial stacking sequences is highly favored both by work of adhesion and interfacial energy. At high temperature and O-poor condition, the metal-metal interfaces show higher thermodynamic stability than metal-oxygen interfaces. The first principles tensile test predicts that the main cause of mechanical failure in Ni₃Ti/Al₂O₃ interface is attributed to the breaking of the Ti-Ni bonds proximity to the interface in the bulk Ni₃Ti phase.