Heat transfer and fluid flow of molten pool during selective laser melting of AlSi10Mg powder: Simulation and experiment

Numerical simulation of heat transfer and fluid flow during selective laser melting (SLM) under point exposure scan of AlSi10Mg powder is performed. The influence of exposure time and point distance on temperature field, velocity field, liquidus duration and dimension of molten pool is investigated. The results show that exposure time has negligible effect on heat transfer and fluid flow and it leads to little change of the dimension of molten pool. With the increase of point distance, the simulated temperature and dimension of molten pool increases. Moreover, the duration of liquidus molten pool changes little with exposure time and point distance. For verifying the accuracy of simulated results, experiments are performed. Compared the dimension of molten pool in simulated results with experimental ones, good agreement is obtained. In addition, when the combination of exposure time and point distance is optimized at 140 μs and 130 μm, a pretty dense and smooth surface free of apparent pores, cracks and balling effect could be acquired. Meanwhile, both the maximum density and microhardness are obtained.