Effect of crystal orientation on the scratching behavior of γ-TiAl alloy nanowires by molecular dynamics simulation

In micro-and-nanomachining, crystal orientation effects significantly influence the plastic deformation, mechanical response, and temperature profile of nanowire materials. This study utilizes molecular dynamics simulation to investigate the process of surface scratching on gamma-TiAl alloy nanowires under six different crystal orientations. The results reveal that the evolution of internal microscopic defects during the surface scratching process is heavily affected by crystal orientation, resulting in distinct dislocation motion-induced shear deformation and extrusion removal by the tool. These factors determine variations in both the shape of the nanowire's surface pile-up and the overall degree of workpiece deformation. Among all cases examined, (001)[110] crystal orientation exhibits easier removal of atoms with minimal internal defects, while (110)[110] crystal orientation shows maximum atom removal without significant overall deformation, both cases demonstrate superior surface morphology and subsurface quality. Furthermore, stress and temperature profiles within abraded atoms and inside the workpiece depend on crystal orientation. These findings provide valuable insights for characterizing surface damage in gamma-TiAl alloy nanowires as well as facilitating the preparation of surface nano-channels.