Quantitative characterization of Inconel 718 alloy powder particle shape and optimization of its SLM forming process
XU Yang1, ZHANG Rong2, XIAO Zhiyu2
1. Nanjing East Precision Machinery Co., Ltd., Nanjing 211100, China; 2. National Engineering Research of Near-Net Sharp Forming for Metallic Materials,South China University of Technology, Guangzhou 510640, China
Abstract：The grain shape of Inconel 718 alloy powder for selective laser melting (SLM) was quantitatively characterized by integrating grain shape parameters. The surface quality, densification behavior, microstructure and mechanical properties of Inconel 718 alloy formed by selective laser melting (SLM) were studied as well. The results show that the overall sphericity of Inconel 718 alloy powder is relatively high. Excessive or deficient volume energy density will lead to obvious nodularization and porosity on the surface of SLM alloy. When the volume energy density is in the range of 120-140 J/mm3, the forming effect of the sample is better. After processed with optimized forming parameters, a large number of directional dendrites form in the deposited sample and the dendrites in molten pool on the side of the sample grow centripetally perpendicular to the boundary. The elongations of specimen at 650 ℃ and room temperature are 1.7 times and 2.6 times higher than these of the standard forging respectively. Although the tensile strength at 650 ℃ is lower than that at room temperature, the elongation of high temperature stretching is 1.5 times that at room temperature.
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2020, Vol. 25 
