In order to improve the fatigue properties of the selected laser melting (SLM) forming AlSi10Mg alloy, a sample of AlSi10Mg composite containing nano-WC was obtained by selective laser melting forming technology. The microstructure of AlSi10Mg alloy sample was observed by OM and SEM. The microhardness and fatigue properties of AlSi10Mg alloy parts were studied by microhardness tester and high frequency fatigue tes-ter. The results show that different solidification conditions in the inside and outside make the growth morphology of the two grains different. The boundary of the pool is cellular crystal and the interior is dendritic crystal. The molten pool is divided into three regions: coarse grain zone, heat-affected zone and fine grain zone. The corresponding average α-Al matrix size is about 1.5 μm, 1 μm and 0.6 μm, respectively, and the average eutectic Si width decreases in turn, about 0.5 μm. The Al-Si eutectic content is (40±3)%, (37±4)%, (30±2)%, respectively, but both are smaller than the eutectic structure of the Al-Si phase diagram at equilibrium, and most of the Si is dissolved in supersaturated form. In the Al matrix. Nano WC is enriched in the grain boundary, and part of the WC undergoes dissolution diffusion burning. The fatigue test results show that the fracture of the specimens has cleavage fracture characteristics, and the fatigue crack originates in the sub-surface layer of the specimens due to the existence of serious inclusions. The high cycle fatigue life of the specimens obeys three-parameter Weibull distribution, and the life prediction model of 3D printed specimens is established. © 2019, Materials Review Magazine. All right reserved.
