Fluid and particle dynamics in laser powder bed fusion

BIDARE, Prveen, BITHARAS, I, WARD, RM, ATTALLAH, MM and MOORE, AJ (2018). Fluid and particle dynamics in laser powder bed fusion. Acta Materialia, 142, 107-120.

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Abstract

In this work, we employ a combination of high-speed imaging and schlieren imaging, as well as multiphysics modelling, to elucidate the effects of the interaction between the laser beam and the powder bed. The formation of denuded areas where the powder was removed during single line and island scans over several layers were imaged for the first time. The inclination of the laser plume was shifted from forwards to backwards by changing power and scan speed, resulting in different denudation regimes with implications to the heat, mass and momentum transfer of the process. As the build progressed, denudation became less severe than for a single powder layer, but the occurrence of sintered and fused powder agglomerates, which were affected by the plume, increased. Schlieren imaging enabled the visualisation of the Ar gas flow, which takes place in the atmosphere above the bed due to the plume, in addition to its interaction with affected particles. Numerical modelling was used to understand and quantify the observed flow behaviour, through the hydrodynamic treatment of the laser plume as a multi-component Ar-Fe plasma. These results promote the characterisation of fluid dynamic phenomena during the laser powder-bed fusion (LPBF) process, which constitutes a key factor in the prevention of defects in additively manufactured parts.

Item Type:	Article
Uncontrolled Keywords:	0204 Condensed Matter Physics; 0912 Materials Engineering; 0913 Mechanical Engineering; Materials; 4016 Materials engineering; 4017 Mechanical engineering; 5104 Condensed matter physics
Identification Number:	https://doi.org/10.1016/j.actamat.2017.09.051
Page Range:	107-120
SWORD Depositor:	Symplectic Elements
Depositing User:	Symplectic Elements
Date Deposited:	20 Mar 2024 15:48
Last Modified:	20 Mar 2024 16:00
URI:	https://shura.shu.ac.uk/id/eprint/33281

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