Revealing the phase-interface properties of the TiB2/TiAl composite from a first principles calculations

Abstract

Revealing the interfacial properties of TiB2/TiAl composites is essential for understanding the mechanism for TiAl alloys reinforced by ceramic particles of TiB2. In this work, the interfacial properties of TiB2/TiAl composites are comprehensively investigated from an atomic point of view. Two different surface terminations of TiB2, and six different atomic stacks of TiAl were considered, resulting in the modeling of twelve different TiB2(0001)/TiAl(111) interfaces. The adhesion, fracture toughness, electronic properties of TiB2(0001)/TiAl(111) interfaces were calculated using first principles based on the density functional theory. The results of work of adhesion calculation showed that the Ti-fcc-hollow-cba interfacial model had the highest interfacial bond strength. Interfacial fracture toughness results indicated that mechanical failure generally occurred in TiAl, but not at the interface and in TiB2. The electronic structure of the interfacial model was analyzed to show that the Ti-terminated interface model was mainly combined through covalent bonds, ionic bonds and metallic bonds; the B-terminated interface model was mainly combined through ionic bonds and covalent bonds.