Ultra-high-speed scratch simulation of single-crystal <i>γ</i> -TiAl alloy at the nanoscale level

Abstract γ -TiAl alloys are increasingly used in aerospace and automotive applications due to their low density and excellent high-temperature properties. However, their poor machinability poses challenges in high-speed manufacturing, especially regarding surface integrity and subsurface damage. Existing studies lack comprehensive insights into the combined effects of tool geometry and scratching velocity on the deformation mechanisms of γ -TiAl alloys under ultra-high-speed conditions. The subsurface damage and material removal behavior of γ -TiAl under scratching speeds 200 m s −1 , 400 m s −1 , 600 m s −1 , 800 m s −1 and 1000 m s −1 are investigated in this work using molecular dynamics simulations. A Ball shaped tool (Case A) and a Berkovich tool (Case B) are employed as the two cutting tool geometries. The findings indicate that chip morphology, dislocation activity, subsurface strain distribution, and thermal response are all considerably changed by higher scratching speeds. The Ball shaped tool facilitates smoother material removal at lower speeds through plastic deformation, whereas the Berkovich tool sharp geometry promotes localized shear deformation and heat concentration at higher speeds, leading to distinct differences in subsurface damage formation. These results demonstrate how important tool geometry is in determining thermal-mechanical behavior and offer atomistic-level insight for improving surface finish, minimizing damage, and extending tool life in ultra-high-speed machining processes of γ -TiAl components.