Nano-tribological behavior and structural evolution of 304 stainless-steel by molecular dynamics simulation and experiment

Abstract

304 stainless-steel has excellent mechanical properties and is commonly used in ultra-precision instrumentation. Nevertheless, the research on the intricate nano tribological behavior of 304 stainless-steel during ultra-precision machining remains limited. In this work, the tribological behavior of 304 stainless-steel is investigated at different indentation depths and scratching velocities by molecular dynamics (MD) simulations and nano-scratch tests. The results show that higher indentation depths lead to more serious damage on the surface and subsurface of 304 stainless-steel. The friction force and friction coefficient also increase significantly with higher indentation depths. It is worth noting that the dislocation density is much smaller at the low-indentation depth, which is due to the large-scale dislocation annihilation at this depth. As the scratch velocity increases, the subsurface shear stress decreases, the dislocation length rises, and it is accompanied by the generation of V-shaped dislocations, which are caused by dislocation entanglement within the substrate. In addition, nano-scratch tests were performed and similar trends were obtained by comparing the results with simulations. This work provides theoretical guidance for a deeper understanding of the deformation behavior of 304 stainless-steel during nano-scratching and its engineering applications at the micron and nano-meter scales.