Abstract:Customized metal powder with a series of specific indexes is the core material to Selective Laser Melting (SLM) process, by which, the fabricated parts exhibit high precision in dimension and excellent properties in mechanics. While, multiple properties of the powder may change during the forming and recycling processes, and that could impair the products’ quality of SLM. This paper focused on the variation of TC4 powder’s properties, including particle morphology, particle size distribution (PSD) and flowability during the recycling process, and the underlying mechanism of the variation was proposed in the meantime. It was observed that the particles still kept morphology of sphere and became smoother with the increasing recycle times; few satellite particles were observed after recycling 14 times; the PSD experienced the course of concentration-dispersion-concentration; the recycled powder showed improved flowability；All the variation above inextricably linked with the percentage decreasing of tiny particles and satellite particles in the recycled powder.The porosity of the forming sample increased firstly and then decreased with the increasing recycle times ; recycle times of TC4 powder had no effect on microhardness.