Tribology and deformation behaviors in gradient-grain stainless steel by experimental study and molecular dynamics simulation

JQ Cao and L Jin and YX Jiang and SJ Xu and YK Wang and JQ Shi, ENGINEERING FAILURE ANALYSIS, 181, 109976 (2025).

DOI: 10.1016/j.engfailanal.2025.109976

Impact and friction and wear are important factors causing the deformation and failure of metal materials. Experiment and molecular dynamics simulation are performed to unravel the tribological performances and plastic deformation in gradient-grain 304 stainless steel. By using the ultrasonic surface rolling (USR) treatment, the gradient-grain sample is prepared, which makes the surface grain refined and thus significantly improves the surface/subsurface hardness from about 266 to 597 HV to reduce friction and wear, with friction coefficient decreasing from 0.75 to 0.46. This validates the fine-grain strengthening mechanism. Then, from the micro perspective, the indentation simulations indicate the phase transformation from both original FCC and indentation-induced HCP stacking faults to BCC. When scratching from coarse to fine grains, the structural evolution reveals the waxing and waning effect of both stacking faults and BCC atom clusters, and the grain boundary causes severer deformation. The migration and redistribution of removed atoms are induced by the frictional and adhesive effects, causing the metallurgical bonding of wear debris on the friction surface. These results enrich the understanding of deformation strengthening and surface preparation processes.

Return to Publications page