Selective laser melting of magnesium alloys: Necessity, formability, performance, optimization and applications

Selective laser melting (SLM), as a rapid prototyping technology, has been widely used to manufacture high-performance metal components with complex structures, which vitally provides a broad platform for the development and application of magnesium alloys. However, the poor laser formability of magnesium alloys has deleterious consequences in the application of SLM processing. This paper discusses the defect formation mechanisms during the SLM process and summarizes characteristics in terms of mechanical properties, oxidation and corrosion resistance. Current optimization schemes are reviewed from both macro and micro perspectives. Firstly, the relationship between process parameters and formability and material properties is clarified, and advanced optimization methods of the design of experiments, physical models, and machine learning are evaluated. Secondly, the effects of alloying elements, composite reinforcement, and post-treatment on the microstructure and properties of the SLMed magnesium alloy are reviewed. Finally, the future application development prospects are envisaged based on the comprehensive review. This work is significantly helpful to a better scientific understanding of SLMed magnesium alloy and puts forward some meaningful guiding opinions for the future work of magnesium alloy manufacturing.