Version 1
: Received: 1 December 2022 / Approved: 1 December 2022 / Online: 1 December 2022 (08:39:46 CET)
Version 2
: Received: 6 December 2022 / Approved: 7 December 2022 / Online: 7 December 2022 (01:59:44 CET)
Bhagat, K.; Rudraraju, S. A Numerical Investigation of Dimensionless Numbers Characterizing Meltpool Morphology of the Laser Powder Bed Fusion Process. Materials2023, 16, 94.
Bhagat, K.; Rudraraju, S. A Numerical Investigation of Dimensionless Numbers Characterizing Meltpool Morphology of the Laser Powder Bed Fusion Process. Materials 2023, 16, 94.
Bhagat, K.; Rudraraju, S. A Numerical Investigation of Dimensionless Numbers Characterizing Meltpool Morphology of the Laser Powder Bed Fusion Process. Materials2023, 16, 94.
Bhagat, K.; Rudraraju, S. A Numerical Investigation of Dimensionless Numbers Characterizing Meltpool Morphology of the Laser Powder Bed Fusion Process. Materials 2023, 16, 94.
Abstract
Microstructure evolution in metal additive manufacturing (AM) is a complex multi-physics and multi-scale problem. Understanding the impact of AM process conditions on microstructure evolution and the resulting mechanical properties of the printed part is an area of active research. In this context, high-fidelity numerical modeling of the AM process at various relevant length-scales has been finding favor. At the meltpool scale, the thermo-fluidic governing equations have been extensively modeled to understand the meltpool conditions and thermal gradients. In many phenomena governed by partial differential equations, dimensional analysis and identification of important dimensionless numbers can provide significant insights into the process dynamics. Hence, the use of dimensionless numbers to understand the complex multiphysics interactions active during metal AM is also gaining traction. In this context, we present a novel strategy using dimensional analysis and the least-squares regression approach, in conjunction with physics-based insights, to investigate the thermo-fluidic governing equations of the Laser Powder Bed Fusion AM process. Through this approach, we identify important dimensionless quantities influencing meltpool morphology. The governing equations are solved using the Finite Element Method, and the model predictions are validated by comparing with experimentally estimated cooling rates, and with numerical results from the literature. We then present our dimensional analysis and define an important dimensionless quantity - interpreted as a measure of heat absorbed by the powdered material and the resulting meltpool. We then use this dimensionless measure of heat absorbed, along with classical dimensionless quantities relevant to the thermo-fluidic governing equations, to investigate advective transport in the meltpool for different metal alloys. This understanding helps us characterize the meltpool aspect ratio and volume in terms of the Marangoni, and Stefan numbers. Further, we study the variations of thermal gradients and the solidification cooling rate using this framework and examine the effect of the Peclet number on the microstructure of the solidified meltpool region.
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
