Simulation of the Thermal Behavior and Analysis of Solidification Process During Selective Laser Melting of Alumina

Selective laser melting (SLM) has rapidly developed in the past decade. High precision-complex ceramics parts can be directly fabricated using this technology. To study the thermal behavior of molten pools in the selective laser melting of alumina （Al2O3）, we established a three-dimensional model based on ANSYS. Then, combined with simulation results, the physical phenomena during the rapid solidification process were discussed. The simulation results showed that the laser power and scanning speed exerts a marked influence on the maximum temperature, liquid lifetime, dimensions, and temperature gradient of the molten pool. Owing to the different temperature gradients in the molten pool, the thermal capillary force on the free surface varies. As a result, a slight difference exists between the stripy solidification structures. Different orientations of columnar crystals can be obtained. The underlying mechanism controls the direction of the temperature gradient with suitable processing routes, such as decreasing the scanning speed.