Microstructure and mechanical behavior of selective laser melted cast carbide reinforced 316 L stainless steel matrix composites

Limited research has been conducted on the selective laser melting (SLM) process for metal matrix composites characterized by high ceramic reinforcement ratios. This investigation explores the viability of the SLM process, particularly the laser powder bed fusion (LPBF) process, for cast tungsten carbide (CC) particle-reinforced 316 L stainless steel composites with CC content ranging from 30 to 40 vol%. A specialized Ni plating procedure was implemented to modify the surface of the original CC particles (Ni/CC) prior to SLM processing. The study revealed that Ni plating plays a pivotal role in enhancing the relative density of the SLMed 316 L-40 vol% Ni/CC composite, while concurrently safeguarding the CC particles from thermal damage during the SLM process. Through a comprehensive design of experiments, the optimal SLM processing parameters were ascertained to maximize the relative density of both 316 L-30 vol% and 40 vol% Ni/CC composites. Moreover, compared to pure 316 L stainless steel, higher CC proportions significantly improved the hardness, compression strength, and wear resistance of the SLMed 316 L-CC composites. •Ni coating is critical to achieving high density of SLMed 316 L-CC composites.•Ni coating reduces the thermal damage of CC particles durng SLM process.•The models of relative density vs. SLM processing parameters was constructed.•CC particles greatly enhanced the mechanical behavior of 316 L-CC composites.