1. Research Center of High-Temperature Alloy Precision Forming, Shanghai University of Engineering Science,Shanghai 201620, China
2. School of Materials Science and Engineering, Shanghai University of Engineering Science, Shanghai 201620, China
Selective laser melting (SLM), as a metal additive manufacturing technology, has the characteristics of flexible control, near net shape and rapid manufacturing. In recent years, it has been widely used in the manufacturing of Ti-6Al-4V alloy, which has a broad application prospect in aerospace and biomedical fields. Due to the particularity of the SLM process, the microstructure of SLM Ti-6Al-4V alloy is significantly different from traditional castings and forgings, and usually has the characteristics of high strength and low plasticity. In order to promote the development of SLM Ti-6Al-4V alloy and improve its mechanical properties, the microstructure of SLM Ti-6Al-4V alloy is reviewed from the following aspects: the phase compositions, the morphology of the prior β grains, the morphology of α′ martensite, the mechanism between α′ martensite and dislocations, the crystallographic orientation characteristics of the prior β grains and α′ martensite. At the same time, the microstructure characteristics and mechanical properties of SLM Ti-6Al-4V alloy under different post-treatment processes are analyzed. Finally, the future development trend of the SLM Ti-6Al-4V alloy is prospected. It will provide a reference for the development, the process optimization and the improvement of mechanical properties of SLM Ti-6Al-4V alloy.