Boundary conditions for simulation of powder bed fusion for metallic glass formation: measurements and calibrations

A finite element model for prediction of the temperatura field in the poder bed fusión process is presented and compared to measurements. Accurate temperatura predictions at the base plate are essential to accurately predict the formation of cristals in a metallic glass forming material. The temperatura measurements were performed by equipping the base plate with thermocouples during manufacturing of a cylinder with the glass forming alloy AMZ4. Boundary conditions for heat losses through the base plate/machine contact interfaces was calibrated to fitthe measurements. Additional heat losses was used to account for radiation at the top Surface and conduction through the poder bed. An interface boundary condition based on conservation of heat flux was examined to match the heat flow to the machine structure and the temperatura predictions was satisfying. Still,temperatura predictions with a constant heat transfer coefficient matched the measurements within 1.5oC during the entire building process of about 9 hours.