Investigating the Effect of Energy Density on Corrosion Susceptibility of Additively Manufactured Thin-walled Cobalt Chrome Alloy

Abstract

Metal additive manufacturing is an innovative technology based on fabricating near-net shaped metallic components from a digital model in a layer-by-layer manner. Although, it has many advantages over conventional subtractive methods, understanding the correlation between process parameters and properties of additively manufactured alloys is key to producing components with optimal performance. Hence, in this study corrosion susceptibility of laser powder bed fusion additively manufactured cobalt chromium alloy (CoCr) alloy produced with three different energy densities (0.58 J/m, 0.87 J/m, 2.26 J/m) was investigated. Some of the CoCr alloys produced were subjected to post-build heat treatment by hot isostatic pressing (HIP). Corrosion resistance of both as-built and HIP CoCr alloys in 0.5 M H2SO4solution at room temperature was investigated using gravimetric method. The results indicated that additively manufactured (AM) CoCr alloy produced with energy density of 0.58 J/m and 2.26 J/m respectively were less susceptible to corrosion compared to that produced with energy density of 0.87 J/m which is the standard energy density recommended by the Original Equipment Manufacturer (OEM). This result was consistent with the trend observed in previously reported mechanical properties of the AM CoCr alloys.