Improving Laser Powder Bed Fusion Printability of Tungsten Powders Using Simulation-Driven Process Optimization...

Area of Science:

• Materials Science
• Additive Manufacturing
• Metallurgy

Background:

• Pure tungsten exhibits desirable properties but is challenging to process.
• Laser Powder Bed Fusion (LPBF) offers potential for complex tungsten part fabrication.
• Understanding process parameter effects is crucial for optimizing LPBF of tungsten.

Purpose of the Study:

• To investigate the influence of process parameters on the density, structure, and mechanical properties of pure tungsten fabricated via LPBF.
• To develop a cost-effective experimental plan using numerical modeling.
• To determine the printability limits of tungsten using LPBF.

Main Methods:

• Numerical modeling of thermal fields and melt pool dynamics.
• Experimental fabrication of pure tungsten specimens using LPBF.
• Characterization of density, microstructure, and mechanical properties (compressive strength, strain to failure).

Main Results:

• Optimized parameters (188 W laser power, 188 mm/s scan speed, 80 µm hatching, 30 µm layer thickness) yielded 93.2% density.
• Achieved ultimate compression strength of 867 MPa and ~7.0% strain to failure.
• Results meet standards for conventionally produced tungsten parts.

Conclusions:

• LPBF is a viable technique for producing high-density, high-strength tungsten parts.
• Key process parameters significantly influence part quality.
• Future work should focus on reducing layer thickness, increasing laser power, hot isostatic pressing, and rhenium alloying for enhanced properties.