Atomic Simulation of Fatigue Crack Growth Mechanism of Single Crystal γ-TiAl Alloy

Abstract

In order to study the relationship of fatigue property、crack growth and organization form of TiAl alloy, the micro crack growth and micro deformation mechanism of single crystal γ-TiAl alloy with an embedded boundary crack under cyclic loading were studied by means of molecular dynamics and velocity loading. Results show that the crack growth process and micro deformation mechanism of single crystal γ-TiAl alloy under cyclic loading were divided into three stages. The mechanical properties are affected by the defects of crack tip lattice distortion,prismatic dislocation slip, Lomer-cottrell dislocation group formation,stacking fault start, deformation twin, etc. and their interaction results in the loading process. The mechanism of crack growth and the mechanism of plastic deformation at different stages were quite different. The research results provide a strong theoretical guidance for improving the performance of γ-TiAlalloys under complex external loading conditions.

Keywords

• molecular dynamics
• embedded boundary crack
• γ-TiAl alloy
• alternate load
• cyclic loading