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

Published

September 10, 2020

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

Pub Type

Conferences

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DOI Link

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 October 16, 2025)