Investigation of temperature gradient and solidification rate in laser-based powder bed fusion using a high-speed camera to evaluate local microstructure characteristics

Laser-based powder bed fusion of metallic materials is widely used in industrial application with major challenges for safety-critical components. However, the layerwise build-up and process parallel monitoring systems offer the potential of direct quality evaluation. This work proposes a novel process monitoring concept to enable the local evaluation of the solidification and consequently an estimation of the microstructure using an on-axis high-speed camera. Based on characteristic intensity values of the phase transitions, the solidification rate and temperature gradient in scan vector direction are determined. A linear regression model estimates the mean grain diameter along the melt path. & COPY; 2023 CIRP. Published by Elsevier Ltd. All rights reserved.