Influence of spatial laser beam profiles on thermal-fluid transport during laser-based directed energy deposition

ABSTRACT

The effects of the two types of typical spatial laser beam profiles (SLBP), including the super-Gaussian profile (SGP) and Gaussian profile (GP), on the thermal-fluid transport during laser-based directed energy deposition (L-DED) were numerically investigated. Considering the laser-powder-pool coupling effect, a comprehensive heat transport model including an input source model, laser-powder coupling model and molten pool thermal-fluid transport model is established. It is found that the SLBP has an important influence on the temperature gradient at the solidification interface and the flow field. Compared with the GP, the temperature gradient at the solidification interface under the SGP is high. Because the Marangoni stress and fluid momentum are in opposite directions, the fluid velocity distribution on the molten pool surface presents an ‘M’ shape. The fluid velocity on the molten pool surface under the SGP is obviously different from that under the GP.

KEYWORDS:

• Laser-based directed energy deposition
• spatial laser beam profile
• coaxial multipowder stream
• thermal-fluid transport
• Numerical investigation

Acknowledgments

The authors thank the State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body in China for his help with the specimen fabrication and characterization.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Science and Technology Foundation of Guizhou Province [grant number [2021]265], National Natural Science Foundation of China (NSFC) [grant number 51975205], Natural Science Foundation of Guizhou University [grant number (2020)15], Talent Project of Guizhou University [grant number [(2015)31] and the Guizhou Science Cooperation Platform Talents [grant number [2019]5616].

Notes on contributors

Jiazhu Wu

Jiazhu Wu is currently a Ph.D. degree holder and lecturer at the Guizhou University in China. His research interests focus on laser additive manufacturing of metals, laser cladding, laser welding, and analytical and computational modelling.

Song Ren

Song Ren is currently master candidate at the Guizhou University in China. His research interests lie in laser additive manufacturing, and analytical and computational modelling.

Yi Zhang

Yi Zhang is currently a Ph.D. supervisor and Professor at the Hunan University in China. His research is mainly focusing on laser materials processing, analytical and computational modelling, and intelligent manufacturing.

Yang Cao

Yang Cao is currently a Ph.D. degree holder and associate Professor at the Guizhou University in China. His research interests include laser additive manufacturing of metals and electromechanical Control.

Dabin Zhang

Dabin Zhang is a Ph.D. supervisor and Professor at the Guizhou University in China. His research interests include laser additive manufacturing of metals and intelligent manufacturing.

Cunhong Yin

Cunhong Yin is a postdoctoral researcher and associate Professor at the Guizhou University in China. He specializes in laser cladding, materials science, and surface and interface science.