Numerical simulation of the thermal behaviors for two typical damping alloys during selective laser melting

Abstract

In this work, the three-dimensional transient temperature field model of two typical damping alloys (i.e., AZ31 Mg alloy and Mn-Cu alloy) were developed during selective laser melting (SLM) using ANSYS finite element analysis software, considering thermophysical properties and phase transformation latent heat of the materials. The simulated molten pool width values of the Mn-Cu alloy show a 6 % error with the experimental SLMed Mn-Cu sample, verifying that the developed model agrees well with the experimental results. Based on the developed numerical model, the temperature distribution, temperature gradients, and cooling rates of the two alloys were investigated during horizontal deposition and vertical deposition of SLM at different scanning speeds (300–700 mm/s). The results showed that the simulated peak temperatures of the AZ31 Mg alloy during the SLM process show a small fluctuation and are well below its boiling point (1107 °C) at the scanning speed of 500–700 mm/s. The temperature gradient increases from 8.5 × 106 °C/m to 20.2 × 106 °C/m with the laser scanning speed. The cooling rate increases from 1.7 × 106 °C/s to 4.1 × 106 °C/s, then reaches stable at 500–600 mm/s. As for Mn-Cu alloy, the cooling rate fluctuates between 7.5 and 8.8 × 106 °C/s during the SLM process at a scanning speed of 300–700 mm/s. By comparing the thermal behavior of the two alloys, the peak temperatures, temperature gradients, and cooling rate of both alloys are closely associated with their thermophysical properties and the laser energy input.