Improving microhardness and wear resistance of 316L by TiO2 powder mixed electro-discharge treatment

Abstract

Electro Discharge Treatment (EDT) has been carried in this study for the surface modification of 316 L stainless steel. The process is carried out in TiO2 powder mixed dielectric medium and assessed in terms of change in microhardness (MH) and wear resistance (WR). The presence of Titania particles, changed structural phases, of the treated specimens, was examined by scanning microscopy (SEM), x-ray diffraction (XRD) respectively. Nano-indentation test revealed the maximum value of microhardness attained (942.90 HV, average) for the specimen machined at the higher discharge current of 28 A in the presence of TiO2. The surface thus produced was 233% more superior in terms of microhardness value compared to bare metal, due to the formation of carbides, silicides and several intermetallic compounds on the treated surface. Furthermore, surface with maximum microhardness also witnessed the dominating wear resistance characteristic with a protective efficiency of 80% compared to the substrate.