Molecular dynamics simulation of the effect of supersonic fine particle bombardment on the mechanical behaviour of ?-TiAl alloy: The effect of grain size

H Cao and ZL Yu and BC Zhou and HY Li and ZT Guo and JQ Wang and WL Yang and RC Feng, VACUUM, 217, 112498 (2023).

DOI: 10.1016/j.vacuum.2023.112498

Due to the nanoscale inverse Hall-Petch (H-P) effect, the grain size exerts a significant influence on the me-chanical behaviour of the material. The impact of supersonic fine particle bombardment (SFPB) on the me-chanical response of ?-TiAl alloy with varying grain sizes was investigated using molecular dynamics simulations. The dislocation density and stress state of the material surface were analyzed before and after SFPB treatment. The results indicate that the degree of grain refinement in the matrix varies depending on the grain size following SFPB treatment. In contrast, the critical average grain size for observing the H-P effect is determined to be 9.96 nm. The hardness of the material increases as the average grain size decreases, but it decreases below the critical average grain size. Moreover, monocrystalline samples exhibit the highest hardness and demonstrate greater sensitivity to elastic recovery in both depth and width directions compared to polycrystalline samples. The variation in grain size following SFPB impact influences the distribution of von Mises stress and hydrostatic stress. The present study investigates the grain refinement and mechanical behaviour of polycrystalline ?-TiAl alloys at the atomic scale, thereby offering valuable insights into the SFPB process.

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