Thermophysical properties of liquid Co–Cr–Mo alloys measured by electromagnetic levitation in a static magnetic field

Abstract

This study aimed to provide thermophysical property data of Co–Cr–Mo (CCM) alloys that are used as biomedical materials to understand and improve additive manufacturing processes. The density, surface tension, normal spectral emissivity, specific heat capacity and thermal conductivity of two CCM alloys that contained a low (0.053 mass%) and a high (0.251 mass%) carbon content were measured in a liquid state using an electromagnetic levitation technique. The liquidus temperatures of the CCM alloys were measured by differential scanning calorimetry. A static magnetic field was applied to the levitated CCM droplets to suppress the surface oscillation and translational motion of the droplets, and convection flow inside the droplet for each property measurement as needed. Uncertainty analysis was conducted for all thermophysical property data. No major difference was found in the thermophysical properties for the low- and high-carbon CCM melts within experimental uncertainty. An ideal solution model reproduced the CCM melt density within experimental uncertainty, however, we obtained large positive excess heat capacities of the CCM melts.