Molecular Dynamics Study on the Surface and Subsurface Damage Mechanisms of Porous γ-TiAl Alloys with Different Pore Morphologies during Grinding

Despite the extensive utilization of porous γ-TiAl alloys in critical sectors such as the aerospace and automotive industries, mitigating surface and subsurface defects during precision machining remains a significant obstacle. This research primarily investigates how varying pore geometries and grinding depths influence the material removal behavior of γ-TiAl alloys during nanogrinding, specifically linking these parameters to surface topography, mechanical feedback, stress field distribution, and dislocation dynamics. Using molecular dynamics (MD) simulation techniques, the study constructs models with distinct pore configurations—including triangular, circular, rectangular, and elliptical shapes—and varying grinding depths to analyze their impact on atomic kinetics and microstructural evolution. The simulation data demonstrate that workpieces characterized by rectangular (RP) and elliptical (EP) pores exhibit reduced zones of atomic pile-up and lower average grinding forces, which effectively mitigate subsurface damage. Conversely, increasing the grinding depth inevitably expands internal high-stress zones and elevates dislocation density, thereby degrading the surface integrity of the processed material. Consequently, relying exclusively on the adjustment of grinding parameters to guarantee superior surface and subsurface quality presents challenges if the influence of pore morphology is ignored. It is concluded that pore structures with elliptical or rectangular geometries are more suitable for maintaining high standards of surface integrity. This study provides profound insights into the atomic-scale damage mechanisms of porous γ-TiAl alloys and offers crucial theoretical guidance for optimizing ultra-precision machining processes for porous materials.