Microstructure-Properties Characterization of Selective Laser Melted Biomedical Co-28Cr-6Mo Alloy

Abstract

Co-28Cr-6Mo alloy (ASTM F75) is widely used in different biomedical applications (dental devices, orthopedic implants, etc.). Casting and metal forming are the two conventional technologies for the fabrication of this alloy. Recently, additive manufacturing has also been adopted. Due to the peculiarities of this technological process, 3D-printed alloys differ from traditionally manufactured alloys in their structure and properties. In the present work, the features of selective laser melted Co-28Cr-6Mo alloy were studied in comparison with its wrought analogue. The study included microstructural characterization (optical and electron scanning microscopy), nanoindentation, and tribological testing. It was shown that the SLM alloy featured the “fish-scale” structure, characteristic of additively fabricated alloys. This structure was composed of fine columnar dendrites. SLM Co-28Cr-6Mo was found equivalent or superior to the wrought alloy in terms of properties, such as hardness, elastic modulus and tribological behavior that makes SLM Co-28Cr-6Mo a promising candidate for implant applications.