Effect of energy density on corrosion susceptibility of additive manufactured thin-walled cobalt chrome alloy

Abstract

Metal additive manufacturing is an innovative technology based on fabricating three dimensional metallic objects from a digital model in a layer-by-layer manner. Although, it has many advantages over conventional subtractive methods, there are still major challenges to be addressed. Hence in this study the effect of energy density on the corrosion susceptibility of Laser Powder Bed Fusion (PBF) additively manufactured cobalt chromium alloy (CoCr) alloy was investigated. The alloy was also 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 H2SO4 solution at room temperature was investigated using gravimetric method. The results of the gravimetric test indicated that the CoCr alloy produced with high and low heat energy density coupons in the as Built and HIP conditions were less susceptible to corrosion compared to the standard energy density coupons recommended by the Original Equipment Manufacturer (RED). This result was consistent with the trend observed in previously reported mechanical properties evaluation of the CoCr AM alloy