Characterisation of heat-treated cobalt–chromium alloy fabricated by selective laser melting

Abstract

The present work focuses on the stress-relief annealing (SRA) modification and porcelain firing (PF) treatment effect in biomedical Cobalt–Chromium (Co–Cr) components for dental applications components produced by the SLM process. The specimens’ phase transformation was examined by X-ray diffraction, optical microscopy, scanning and transmission electron microscopy, combined with energy dispersive X-ray spectroscopy. The corresponding mechanical properties were assessed by compression tests and Vickers hardness measurements. The matrix microstructure consisted mainly of the FCC γ phase with a small amount of the HCP-structured ϵ phase. SRA at 750°C and 950°C, followed by PF at the 930°C treatment, increased the percentage of the ϵ phase and caused the precipitation of fine carbides and intermetallic precipitates, thus improving the final mechanical properties.