SLM process of pure tungsten

• Main Author: Teo, Renjie
• Other Authors: Matteo Seita
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2021
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/147735
• Institution: Nanyang Technological University

The mechanical and microstructural properties of pure tungsten produced using Laser Bed Additive Manufacturing by Selective Laser Melting (SLM) are evaluated. Due to the poorly understood nature of tungsten SLM, initial observations were made by looking at how the volumetric energy density (VED) and other printing parameters affect the surface topography via laser confocal microscopy. Subsequent experiments then focused on actual bulk prints that were then analyzed, looking for how the density of the samples were changed due a change in parameters through optical microscopy. Subsequently, after chemical etching of the pure tungsten samples, they are examined to look at grain structure, melt pools and porosity. Characterization techniques such as electron backscatter diffraction was utilized to take a closer look at microstructure. The results were then analyzed by comparing the density and porosity of these samples generated with different parameters, and then cross referenced using these different techniques to corroborate or support resulting conclusions and hypotheses. Possible research directions are also proposed and theorized on in this report using data-driven conclusions from earlier experiments. By understanding how SLM printing parameters affect the mechanical properties of these materials, and how certain alloys affect the microstructure, we can expand on the versatility of AM metals in industries by finding ways to optimize the technique for more applications.