Real-time monitoring of laser powder bed fusion process using high-speed X-ray imaging and diffraction

By Cang Zhao, K. Fezzaa, Ross W Cunningham, H. Wen, F. De Carlo, Lianyi Chen, Anthony D. Rollett, T. Sun. Scientific Reports, 2017

713 citations recorded by the source corpus.

We employ the high-speed synchrotron hard X-ray imaging and diffraction techniques to monitor the laser powder bed fusion (LPBF) process of Ti-6Al-4V in situ and in real time. We demonstrate that many scientifically and technologically significant phenomena in LPBF, including melt pool dynamics, powder ejection, rapid solidification, and phase transformation, can be probed with unprecedented spatial and temporal resolutions. In particular, the keyhole pore formation is experimentally revealed with high spatial and temporal resolutions. The solidification rate is quantitatively measured, and the slowly decrease in solidification rate during the relatively steady state could be a manifestation of the recalescence phenomenon. The high-speed diffraction enables a reasonable estimation of the cooling rate and phase transformation rate, and the diffusionless transformation from β to α’ phase is evident. The data present here will facilitate the understanding of dynamics and kinetics in metal LPBF process, and the experiment platform established will undoubtedly become a new paradigm for future research and development of metal additive manufacturing.

Subfields: Automotive Engineering, Biomedical Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/cfe9b7c07bdec57699f829f201861987790676cf

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Citations in the corpus

Material-structure-performance integrated laser-metal additive manufacturing (2021, background): “The direct experimental approach by in situ high-speed synchrotron x-ray imaging (139, 140, 146–149) provides the advanced technical means to capture the rapid changes in these highly dynamic phenomena with high spatial and temporal resolution (147, 148), revealing different paradigms and mechanisms”
Keyhole-induced porosities in Laser-based Powder Bed Fusion (L-PBF) of Ti6Al4V: High-fidelity modelling and experimental validation (2019, background): “Moreover, online monitoring requires a series of sophisticated preparations and calibrations, a priori [14], [16], which in turn increases the total analysis time considerably.”
The barriers to the progression of additive manufacture: perspectives from UK industry (2018, methodology): “Zhao et al. (2017) present in situ monitoring of the physical processes during powder bed fusion using high-speed x-ray imaging.”
Modeling of solidification microstructure evolution in laser powder bed fusion fabricated 316L stainless steel using combined computational fluid dynamics and cellular automata (2019, background): “Different from the traditional welding models, the geometrical irregularity of the sintered powder often causes more complicated temperature distribution and unstable fluid flow [12-14].”