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Simultaneous High-speed X-ray Transmission Imaging and Absolute Dynamic Absorptance Measurements during High-power Laser-metal Processing

Published

Author(s)

Brian Simonds, Jack R. Tanner, Alexandra B. Artusio-Glimpse, Paul A. Williams, Niranjan Parab, Cang Zhao, Tao Sun

Abstract

During high-power laser metal processing, the absorbed light is intimately related to the molten metal cavity shape. For the first time, we directly and simultaneously observe this relationship by implementing state-of-the-art techniques of high-speed x-ray imaging and integrating-sphere radiometry. Experiments were performed on Ti-6Al-4V solid and powder under single spot laser illumination, and under laser conditions that cause keyhole formation and collapse. The x-ray imaging corroborates that a dramatic rise in laser absorption is due to keyhole formation. We also find that keyhole area correlates most strongly with energy absorption followed closely by depth. Furthermore, time synchronization reveals correlations between keyhole fluctuations and rapid dips in energy absorption that occur during nominally “stable” keyhole conditions. For instance, we discover that rapid, momentary decreases in absorbed energy of over 25% correlate with instantaneous keyhole collapses. These observations give crucial, quantitative data for computational modeling whose aim is to predict porosity and defect formation.
Proceedings Title
Proceedia CIRP
Volume
94
Conference Dates
September 6-10, 2020
Conference Location
Fuerth
Conference Title
LANE 2020 - 11th CIRP Conference on Photonic Technologies

Citation

Simonds, B. , Tanner, J. , Artusio-Glimpse, A. , Williams, P. , Parab, N. , Zhao, C. and Sun, T. (2020), Simultaneous High-speed X-ray Transmission Imaging and Absolute Dynamic Absorptance Measurements during High-power Laser-metal Processing, Proceedia CIRP, Fuerth, -1, [online], https://doi.org/10.1016/j.procir.2020.09.135 (Accessed April 20, 2024)
Created September 9, 2020, Updated December 22, 2020