Effect of Heat Treatment on Microstructure and Mechanical Behavior of Cu-Bearing 316L Stainless Steel Produced by Selective Laser Melting

Cu-bearing stainless steels (SSs) with high strength, excellent plasticity, and effective antimicrobial properties hold significant potential for applications in the marine industry. In this study, Cu-bearing SSs with copper ranging from 0 to 6.0 wt% were successfully prepared using selective laser melting (SLM) technology. For the Cu-bearing SSs with different copper contents, the effect of heat treatment on the microstructural and mechanical behaviors was studied systematically. Microstructural observations revealed that the subgrain size of Cu-bearing SSs increased with heat treatment at 500 degrees C and 700 degrees C for 6 h. Furthermore, the tensile strength and elongation increased after the heat treatment temperature due to the combined effect of dislocations, twins, and epsilon-Cu precipitated phases. Notably, after heat treatment at 700 degrees C, the SLM4.5Cu sample exhibited an abnormal rise in tensile strength and elongation. This finding suggests that the diffusion strengthening caused by epsilon-Cu precipitates exceeded the stacking fault energy. Consequently, the tensile strength and elongation reached 693.32 MPa and 56.94%, respectively. This work provides an efficient approach for preparing Cu-bearing SSs with exceptional strength and plasticity.