Atomic simulation of the effect of supersonic fine particle bombardment process parameters on the mechanical properties of polycrystalline γ-TiAl alloy

Abstract

γ-TiAl alloys are the most promising lightweight high-temperature structural materials, but the materials often fail from the surface, which is mainly attributed to the stress state of the material surface. In this paper, the orthogonal experiment method and molecular dynamics modeling are used to choose a set of the best process parameters for supersonic fine particle bombardment (SFPB). Furthermore, by determining the optimal process parameters, this study examines the influence of residual stress distribution on the mechanical properties of the material under various process conditions. The simulation results reveal that the residual stress distribution is minimally impacted by particle radius, nonetheless, maintaining a moderate level of compressive residual stress within a specific range can substantially augment both the tensile strength and indentation hardness. An increase in the number of particles results in a more uniform distribution of surface residual stresses. Conversely, an increase in the number of impacts causes stress concentration to intensify at the particle’s contact point, and thus a deeper distribution of residual stress is observed. This study illustrates how the mechanical properties of polycrystalline γ-TiAl alloy are affected by the process parameters of SFPB in terms of atomic size in order to develop and select the optimal SFPB parameters.