Influence of low temperature heat treatment on microstructure, corrosion resistance and biological performance of 316L stainless steel manufactured by selective laser melting

This study investigates the microstructure and corrosion behavior of the selective laser melted (SLM) 316L stainless steel in a Ringer’s solution. Besides, the biocompatibility of the fabricated SLM alloy was investigated using MG63 cells. The wrought, SLM, and heat-treated at 450 °C (SLM-450) stainless steel alloys were picked for the investigation. Microscopy evaluation indicated that SLM and SLM-450 samples showed a cellular morphology due to the fast cooling rate the SLM process. SLM-450 sample showed a better corrosion performance compared to other samples. Charge transfer resistance of the SLM-450 after 330 h of immersion was two times higher than wrought and SLM samples in the corrosive solution, respectively. Moreover, the SLM-450 alloy revealed the highest biocompatibility, most probably because of the stress relief after heat treatment, the lower release of toxic cations, and the presence of round MnSiO3 phase in the SLM-processed alloy.