Multi-Physics Modeling of Melting-Solidification Characteristics in Laser Powder Bed Fusion Process of 316L Stainless...

Area of Science:

• Materials Science and Engineering
• Additive Manufacturing
• Computational Modeling

Background:

• The quality of workpieces in laser powder bed fusion (LPBF) is critically dependent on the melting and solidification behavior of materials like 316L stainless steel.
• Understanding these complex thermal and fluid dynamics is essential for achieving desired material properties and structural integrity.

Purpose of the Study:

• To develop and utilize a multi-physics model to simulate the melting-solidification process in the LPBF of 316L stainless steel.
• To investigate the influence of key process parameters (laser scanning speed, hatch space, laser power) on the thermal characteristics and defect formation during LPBF.

Main Methods:

• A finite volume method (FVM) based multi-physics model was employed to simulate the LPBF process.
• The model incorporated phase change, temperature gradient effects on surface tension, and recoil pressure from metal vapor.
• Simulations were performed to analyze temperature distribution, keyhole depth, and overall workpiece quality.

Main Results:

• The study analyzed the impact of varying laser scanning speed, hatch space, and laser power on the molten pool dynamics and thermal profiles.
• Keyhole depth and temperature distribution were found to be sensitive to changes in these process parameters.
• The simulation results provide insights into the relationship between process parameters and potential defects.

Conclusions:

• The developed multi-physics model accurately simulates the complex phenomena occurring during the laser powder bed fusion of 316L stainless steel.
• Optimizing laser scanning speed, hatch space, and laser power, guided by these simulation results, can significantly improve workpiece quality.
• This research provides a valuable tool for guiding process parameter optimization in additive manufacturing.