Investigations on Water Jet Peening of AZ31B Mg Alloy for Bio Medical Implants

Abstract Among different unconventional peening technique, water jet is cold working process has capable to produce surface topography on wide variety of materials. This paper deals with the effect of water jet peening on the corrosion resistance and the surface topography of AZ31B Mg alloy. Variations in water jet peening variables including standoff distance, traverse speed and multiple passes have been employed in this study. A study of the enhancement in hardening and roughening effect was made following the peening process. 29.44% Improvements in microhardness and 31.06% reduction in surface roughness were observed on the peened surfaces. Optimal peened surface was obtained through use of the multi-objective optimization technique, namely, TOPSIS, which utilizes response variables such as micro hardness and surface roughness. In this study, Surface Topography, XRD Analysis and Electrochemical test were conducted. In addition, analysis of the Microstructure of corroded region was made in the unpeened and optimized peened surfaces. Surface topography parameters including Sa, Sq, SSk, Sku results confirmed the suitability of the peened surface for ooseointegration and cell growth. FWHM value measured from XRD peaks showed the formation of grain refinement on the peened surface, and the results showed promising improvements in the corrosion resistance compared to the unpeened AZ31B Mg alloy.