Mechanical property, corrosion behavior and cytocompatibility of CoCrMo for dental application: A comparative study of cast and laser powder bed fusion

In this work, by employing powders sourced directly from the original ingot for additive manufacturing, we enabled a comparative overview of the performance between CoCrMo manufactured via laser powder bed fusion (LPBF) and those in their original cast condition. Microstructural analysis revealed that the cast (CT) alloy predominantly consisted of coarse grains with distribution of sigma phase, while the LPBF process resulted in a refined grain structure devoid of the sigma phase. The tensile strength tests demonstrated that the LPBF-derived CoCrMo alloy had substantially greater tensile strength, and ductility compared to CT alloy. Corrosion tests indicated superior corrosion resistance in the LPBF alloy, albeit with a lower metal ion release. In vitro assays confirmed that LPBF CoCrMo alloys displayed favorable cytocompatibility. Consequently, it is concluded that the CoCrMo alloy processed through laser powder bed fusion exhibited enhanced mechanical performance and corrosion resistance. These improvements are primarily attributed to the transformation of the original coarse columnar grain structure through the LPBF technique.