Temperature induced nano-scratch responses of γ-TiAl alloys revealed via molecular dynamics simulation

Abstract

The mechanical behavior and deformation mechanism of γ-TiAl alloys during nano-scratch at elevated temperature were investigated through molecular dynamics (MD) simulation, in terms of the scratching force and friction coefficient (COF), surface morphology and atomic displacement, von Mises stress and shear strain, and dislocation density. The elevated temperature induced weakening of surface friction, normal forces and COF. The gradually improved plastic deformations induced by the elevated temperatures were also confirmed by the enhanced number of atoms in the high strain zone. Meanwhile, the temperature-dependent amorphous transformation restrained the dislocation movement, as the dislocation density at elevated temperature was remarkably lower that at room temperature (RT). Therefore, the γ-TiAl alloy exhibited superior wear resistance at elevated temperature at the atomic scale owing to the amorphization and softening behaviors.