Three-dimensional finite element thermal analysis in selective laser melting of Al-Al2O3 powder

The selective laser melting (SLM) of aluminium-based composites continues to be a challenge due to the high reflectivity, high thermal conductivity and oxidation of aluminium, all of which directly influence the thermal performance of each layer during SLM. Due to the extremely rapid melting and cooling rate of aluminium, however, it is difficult to measure thermal performance within practical SLM applications. A three-dimensional finite element simulation model is thus developed in this study to simulate the transient temperature distribution and molten pool dimensions of the premier layer during the SLM of Al-Al2O3 composite powder. In order to produce high-quality parts with minimum defects in a highly efficient manner, the predicted optimum volumetric energy density is found to be 40 J/mm3, with laser power 300 W, scanning speed 1000 mm/s, hatch spacing 150 μm and layer thickness 50 μm; the molten pool size that is produced is 165 μm in length, 160 μm in width and 77 μm in depth, with a predicted maximum temperature of around 3400°C. All of these factors may contribute to the creation of good metallurgic bonding.