Molecular dynamics simulations of void growth in γ-TiAl single crystal

Abstract

Molecular dynamics simulation was performed to study the growth of spherical nano-voids and the fracture properties of γ-TiAl single crystal. It is found that the emission of shear loops is the primary mechanism of the void growth: continued production of dislocation cores and the propagation of shear loops make the void grow. Cracks originate from the deformed area near the void surface. As the cracks propagate to the void surface and to the crystal boundaries, γ-TiAl single crystal finally fractures. The dependence of the void growth on the specimen size, strain rate, and void volume fraction was also investigated. The incipient yield strength decreases as the specimen size or void volume fraction increases, but increases with the increase of the strain rate. Young’s modulus is only sensitive to the void volume fraction.