Effect of Subsequent Heat Treatment on Nano-Tribological Behavior of the Co-Cr Medical Alloy Fabricated by Selective Laser Melting

To apply the selective laser melting (SLM) fabricated dental Co-Cr alloy prosthesis in clinical use cases, investigations of the heat treatment (HT) effect on tribological properties are necessary, which is important to the reliability and durability. In this paper, the tribological characteristic of the SLM Co-Cr alloy underwent various HT temperature and was investigated by in-situ nano-scratch with progressive loading, normal loading, and cyclic loading test methods. As results, the scratch mechanism of all the samples is adhesion mechanism regardless of the loading method. Moreover, as the HT temperature increased, the wear resistance initially increased and then dropped, and the critical load, nano-hardness, and H³/E² value obtain their maximum value at 950 °C, as well as the lowest scratch and residual depths, indicating the highest scratch resistance. The presented work could facilitate a comprehensive understanding of nano-tribological behaviors of the SLM fabricated Co-Cr alloy.