Ultrafast dynamics of laser-metal interactions in additive manufacturing alloys captured by in situ X-ray imaging
By Aiden A. Martin, N. Calta, J. Hammons, S. Khairallah, M. Nielsen, R. Shuttlesworth, N. Sinclair, Manyalibo Matthews, J. Jeffries, T. Willey and 1 more. Materials Today Advances, 2019
190 citations recorded by the source corpus.
Abstract Advanced in situ characterization is essential for determining the underlying dynamics of laser-material interactions central to both laser welding and the rapidly expanding field of additive manufacturing. Traditional characterization techniques leave a critical experimental gap in understanding the complex subsurface fluid flow and metal evaporation dynamics inherent in laser-induced heating of the metal. Herein, in situ ultra-high-speed transmission X-ray imaging is revealed to be essential for bridging this information gap, particularly via comparison with and validation of advanced multiphysics simulations. Imaging on submicrosecond timescales enables correlation between dynamics of the laser-generated vapor–liquid interface and melt pool surface instabilities in industrially relevant alloys. X-ray imaging and complimentary simulations reveal vapor depression oscillations and rapid expansion due to reflection of the processing laser from the front surface of the vapor depression. Pore formation studies at steady state and during prompt removal of laser heating at the end of track reveal that the rapidly solidifying melt pool traps pores near the base of the vapor-filled depression. Moreover, pores within the melt pool are entrained by Marangoni convection which overcomes the force of buoyancy and forces the pores downward from the surface immediately before solidification. Observed solidification kinetics, consistent with previous results, give insight into surface morphology and porosity in the processed material. The information presented here is key for defining the physical models that describe laser-material interaction and ultimately increases our understanding of the emerging field of laser-based metal additive manufacturing.
Subfields: Computational Mechanics, Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/97558c06b07a317768feede341fba8ef83f26a13
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Computational Mechanics
In Mechanical Engineering
Citations in the corpus
- Keyhole-induced porosities in Laser-based Powder Bed Fusion (L-PBF) of Ti6Al4V: High-fidelity modelling and experimental validation (2019, background): “In this work, a combined numerical and experimental investigation is carried out to study the formation of keyhole and keyhole-induced porosities during single track L-PBF of a Ti6Al4V alloy.”