Microscale Analysis of Melt Pool Dynamics Due To Particle Impingement and Laser-Matter Interaction in the Spot Laser Metal Deposition Process

• Published in: JOM (1989) Vol. 72; no. 3; pp. 1138 - 1150
• Main Authors: Chouhan, Arvind, Aggarwal, Akash, Kumar, Arvind
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2020; Springer Nature B.V
• Subjects: Additive Manufacturing: Validation and Control; Chemistry/Food Science; Dimensionless analysis; Dimensionless numbers; Earth Sciences; Energy; Energy transfer; Engineering; Entrapment; Environment; Fluids; Free surfaces; Heat; Interfaces; Laser deposition; Lasers; Marangoni convection; Particle impact; Particle interactions; Physical properties; Physics; Researchers; Simulation; Stainless steel; Velocity
• ISSN: 1047-4838; 1543-1851
• DOI: 10.1007/s11837-019-04000-x

In situ observation of the melt pool in the laser metal deposition process reveals the highly unstable and dynamical nature of the free surface due to impinging particles. Surprisingly, no reported numerical work has taken into account the effect of individual particles; they rather use the continuum approach to mass addition, leading to less accurate predictions. In this article, high-fidelity, experimentally validated, free surface thermo-fluidic modelling is done at the micro-scale utilizing open-source codes. The physical phenomena governing the laser metal deposition process, including free surface convection driven flow, mass momentum and energy transfer due to impinging particles, laser-particle interaction, gas entrapment, etc., have been considered. The influence of impinging particles on melt pool dynamics was studied by carrying out analysis using dimensionless numbers (Peclet, Marangoni and Grashof). The finding reveals that during heating the melt flow is mainly driven by the Marangoni force; subsequently, during particle addition, forces due to both particle impact and Marangoni convection play the dominant and counter-acting role.