Molecular Dynamics Simulation of the Tensile Deformation Behavior of the γ(TiAl)/α2(Ti3Al) Interface at Different Temperatures

The interface plays an important role in the deformation process and in improving the strength of TiAl alloy. In this study, the molecular dynamics method and the embedded atom model (EAM) potential function were used to simulate the tensile deformation process and the fracture mechanism of the γ(TiAl)/α2(Ti3Al) interface at different temperatures. The results showed that the γ(TiAl)/α2(Ti3Al) coherent interface and the semi-coherent interface exhibited different fracture mechanisms during the tensile fracture process. The tensile strengths of the coherent interface and the semi-coherent interface were equivalent, but the elongation of the semi-coherent interface was significantly higher than that of the coherent interface. The coherent interface exhibited brittle fracture characteristics as the stretching temperature increased. When stretched at 300 K and 600 K, the γ(TiAl)/α2(Ti3Al) semi-coherent interface exhibited brittle fracture characteristics. When stretched at 800 K, 1000 K and 1200 K, the semi-coherent interface exhibited certain ductile fracture characteristics. The main reason for this was that, the atomic arrangement at the semi-coherent interface could enter a disordered state more easily as the temperature increased relative to the coherent interface. The existence of these microvoids could produce dislocations, dislocations could passivate the microvoids, to play a strengthening role in the deformation process.