Fabrication and Tribological Functions of Micro Dent Arrays on Ti-6Al-4V Surface by Laser Shock Peening

Surface patterning has become a valuable technique for fabricating micro dents which may act as lubricant reservoirs to reduce friction and wear in sliding and rolling contact applications. In this paper, the use of laser shock peening (LSP) along with an automatic X-Y table proves to be an attractive and reliable method for producing micro dent arrays with enhanced surface integrity. Surface topography and profiles of the fabricated micro dent arrays on polished Ti-6Al-4V have been characterized. The effect of dent arrays with different density on friction reduction at low and high viscosity lubrication was investigated. An acoustic emission (AE) sensor was used to on-line monitor friction and wear processes. It was found that a surface with 10% dent density provides better effect in reducing coefficient of friction (CoF) than those of smooth surface and a surface with 20% dent density. It was shown that there is a strong correlation between acoustic emissions (AE) signals, especial AE cumulative counts and wear rate.