Study of energy density on mechanical properties of laser additively manufactured AlSi10Mg alloy

Selective laser melting (SLM) technology is widely used in additive manufacturing of three-dimensional complex parts, but its high temperature gradient produces residual stresses on the components, which significantly affects the quality of the components. A 3D finite element model (FEM) of AlSi10Mg is built to simulate the SLM forming process, and evolution of residual stresses are analysed, as well as the effects of different exposure times and laser powers on residual stresses. The outcomes demonstrate that the distribution of residual stresses is characterised by periodicity, and the stresses in the scanning channel and between adjacent scanning channels, and at the lap of the melt pool are obviously larger than those in other regions. The residual tensile stress enhances with the magnify of laser power, however when the laser power maximise to a certain value, the remelting effect is significantly enhanced, and the residual stress is better released. The longer the exposure time is, the more uniform the heating of the melted area, the slower the cooling rate, and the gradual reduction of residual stress to ensure the processing quality.