Temperature Field Analysis And Microstructure Evolution Of Selective Laser Melting On Inconel 718 Superalloy

Selective laser melting(SLM),as one of the most important branches of additive manufacturing(AM)techniques,exhibits a great potential for direct fabricating 3D parts with flexibility in materials and shapes.At present selective laser melting has been widely used in aerospace and medical fields.However,the experimental measurements of thermal physical statistics during SLM process are considered to be difficult because it involves the fast moving of laser energy source,the limited liquid lifetime of the molten pool and the extremely high cooling rate of the elevated-temperature melt.Based on ANSYS 16.0 software,considering the latent heat of material phase change and the thermophysical properties of materials,the loading heat source is set to Gaussian distribution,and the APDL parametric language command flow is used to generate the selective laser Finite element analysis model of three-dimensional temperature field.The effects of laser power and scanning speed on the temperature field distribution were studied.The size of the molten pool and the maximum temperature of the instantaneous temperature were also investigated.The effects of laser power and scanning speed on the temperature field distribution were investigated.The influence of laser power and scanning speed on the temperature field and bath of IN718 Ni-base superalloy was investigated.The influence of laser power and scanning speed on the temperature field and bath of IN718 Ni-base superalloy was also discussed with the increase of laser power and the increase of scanning speed.With the increase of the number of layers,the heat-affected zone of the whole temperature field is expanding,and the instantaneous maximum temperature of each layer is increasing.With the increase of the number of layers,The width and depth of the molten pool is also increasing.In this paper,the evolution of microstructure in the process of selective laser melting has been studied.The results show that at the low magnification,the microstructure of the molten pool is existed in the longitudinal section,and the molten channel exists in the cross section.At high magnification,the dendrites are observed in the longitudinal section,and the microstructures of the cellular crystal are observed in the cross section.During to the selective laser melting process,the matrix ? phase and the strengthening phase ? '' phase are present in the molded article.According to the analysis,there is no segregation and aggregation phenomenon in the selective laser melting sample.