The thermal-mechanical behavior of WTaMoNb high-entropy alloy via selective laser melting (SLM): experiment and simulation

The refractory high-entropy alloy (HEA) has excellent heat tolerance and high strength-to-weight ratio. In this study, the thermal-mechanical behavior was examined with the selective laser melting (SLM) process to fabricate a WTaMoNb refractory HEA. The corresponding experiment was conducted to investigate the formation of HEA parts. A heat transfer model and a stress and strain model of the SLM process were built. The finite difference (FD) coupled with the finite element (FE) approach was utilized to simulate the 3D temperature distribution and thermal stress, during a continuous SLM process. The HEA samples with several layers could be deposited at a power p = 400 W and a scanning velocity v = 250 mm s(-1). Warping and cracking deformation occurred over 12 layers due to thermal stress. The thermal-mechanical analysis through simulation demonstrated that the uneven temperature distribution in the entire part caused warping and cracking defects. Subsequently, the process was improved based on the thermal-mechanical analysis and simulated trials. The experiment with the improved process was conducted and verified to be effective for the production of alloys of unlimited layer numbers without cracking defects. The thermal and mechanical models coupled with the FD-FE method could be successfully utilized to simulate and improve the entire SLM process.