Numerical simulation and experimental study of the 7075 aluminum alloy during selective laser melting

ANSYS APDL 19.0 was used to establish the thermal structural coupling finite element model of 7075 aluminum alloy, formed by selective laser melting (SLM). The effects of different process parameters on temperature and stress fields were studied by combining numerical simulation and experiment. The size of the molten pool increases with the increase of laser power or the decrease of scanning speed. The cooling rate increases with an increase of laser power or scanning speed. The increase of laser power or scanning speed leads to the increase of residual stress, and the maximum residual stress is located in the overlapping area of the welding pool. The effects of different process parameters such as scanning strategy, laser power, and scanning speed on the forming quality and microstructure of the sample were obtained. The sample formed by checkerboard scanning strategy has the lowest porosity and crack number. With the increase of laser power or the decrease of scanning speed, the number of holes decreases, and the size of pores between the cellular structure in the columnar crystal increases. Compared with laser power, scanning speed has a greater influence on the microstructure of the sample formed. The experimental results are in good agreement with the numerical simulation results.