Micro-dimple textured surface produced by laser-induced particle impact test and improving tribological performance

This study develops a surface treatment based on the laser induced particle impact test (LIPIT) to improve the tribological performance of a material surface. Using pulsed laser ablation, LIPIT enables us to conduct hypervelocity microparticle projectile impacts on a material surface. With LIPIT, microparticles impact the material surface with a velocity of 400 m/s to 750 m/s depending on particle mass. This results in a deep impact crater whose cross-sectional profile becomes textured surfaces which may improve tribological performance. A finite element method simulated elastoplastic deformation by a single particle impact. It is shown that LIPIT produces a deep impact crater, compared with general shot peening (SP). Next, LIPIT was conducted repeatedly to create a textured surface for a wide area of SUS316 stainless steel. To compare this with other surface treatments, SP and SP with polishing were additionally conducted. It is revealed that the LIPIT crater has a higher aspect ratio (deep dimple structure), producing a unique LIPIT treated surface. To investigate tribological performance, this study conducted a ball-on-plate type wear test with reciprocating sliding. The wear test was also conducted for non-treatment, LIPIT, SP, and SP with polishing. It is shown that the LIPIT treated specimen is the low friction coefficient. In addition, the onset of seizure wear significantly delays owing to LIPIT. These results indicate that LIPIT mitigates frictional resistance since the dimple textured surface produced by LIPIT enhances lubricant retention.