Effect of Hole Size on Single Crystal γ-TiAl Alloy Crack Propagation Based on Molecular Dynamics Simulation

Molecular dynamics method has been applied to research the process of crack propagation of single crystal gamma-TiAl. The atomic trajectory figure, energy evolution and the relationship between stress and strain were obtained to study the hole size effect. The results indicate that the initiation stress decreases with hole size increasing. After the crack combines with the hole, when R=0.4001 nm, crack occurs at the center of hole boundary after hole deformation, and it propagates along the direction of [100] until material fracture, and mother-child model is found; when R=0.8002 nm, crack occurs at one corner after hole deformation, and it propagates along the direction of [100] until material fracture; when R=1.2003 nm, crack occurs at two corners after hole deformation, and it propagates along the direction of [110] and [1 (1) over bar0], mother-child model is found at the direction of [110], and child crack occurs at boundary which combines with crack in this direction and propagates until material fracture. In addition the crack propagation is inhibited by the hole.