Simulation of Residual Stress of SLM Additive Manufactured Micro-annular Inconel718 Components

During selective laser melting additive manufacture, due to local high temperature, the material undergoes non-uniform deformation and produces residual stress, which greatly affects the processing quality of the parts. A numerical model of selective laser melting process is established by means of thermo-mechanical sequential coupling, thermo-elastic-plastic model, metal powder-solid two-phase transformation, birth-death element and restart technology. Then the influence of geometric configuration on residual stress is studied. Compared with experimental results in literatures, the accuracy of the simulation algorithm is verified. The results show that the residual stress increases with the decrease of curvature of the parts, and the compressive residual stress mainly distributes on the inner and outer walls of the parts, while the tensile residual stress mainly distributes on the area near the middle diameter of the parts. With the increase of the height of the additive, the residual stress decreases first and then increases, and gradually tends to be stable.