Investigation of Microstructural Characteristics of Cobalt Chromium Molybdenum Additively Manufactured Using Laser Directed Energy Deposition Technology

The present work conducted a comprehensive microstructural characterization of the cobalt chromium (CoCr) alloy manufactured via laser direct energy deposition (L-DED) technology. High-resolution microscopy using both optical and electron microscopy were carried out for the identification of the grain morphology, pores, and grain boundaries. In addition, the crystal structures of the major phases, lattice parameter, interplanar atomic distances, and crystallite size were calculated from X-ray diffraction (XRD) analysis and the transmission electron microscopy (TEM). All characterization experiments were conducted on the conventionally processed CoCr sample as well for the reason of comparison. While the ε-HCP and γ-FCC cobalt phases were detected in both samples, the lower volume fraction of the ε-HCP structure was measured in the L-DED sample. A slight difference was found between the values of the calculated lattice parameters of the two CoCr alloys. Finally, the TEM confirmed the existence of the planes and the crystal structures as detected by the XRD experiment. This is preliminary work; future studies on the microstructural characteristics as well as the mechanical properties of the different alloys will help to establish a relationship between the process-microstructure-properties for the L-DED processed metallic materials.