Atomistic-scale insight into deformation behavior and microstructural response of NiCrFeCoCu superalloy processed by laser shock peening

Laser shock peening, as an advanced surface modification technology, can significantly improve the mechanical properties of metal materials. However, experimental research can't timely explore the dynamic evolution process of microstructures from an atomic perspective. Therefore, an innovative and effective molecular dynamics simulation method was proposed to deeply analyze the dynamic deformation behavior and microstructural evolution mechanism of NiCrFeCoCu superalloy subjected to LSP treatment. The separation of double waves and the progression of plastic deformation were analyzed in terms of particle velocity and stress distributions. Meanwhile, dislocation interactions were characterized to elucidate the underlying mechanisms of microstructural changes. The evolution of stacking faults was discussed through the formation of hexagonal close-packed lath structures and twin boundaries. The results indicated that higher shock velocities lead to more intense plastic deformation, enhanced dislocation interactions and pronounced formation of stacking faults, which evolve into hexagonal close-packed lath structures under high-velocity shock. Furthermore, twin boundaries formed after relaxation were directly initiated by intrinsic stacking faults, without the intermediacy of extrinsic stacking faults. Finally, the grain refinement mechanism in the NiCrFeCoCu superalloy treated by laser shock peening was explored, revealing that the degree of refinement increases with higher shock velocities. This work is expected to provide an advanced technological approach and research method for improving the comprehensive mechanical properties of metal materials, and further promotes the more effective application of LSP technology in fatigue resistant manufacturing.