Microstructure and Elevated Temperature Flexure Testing of Tungsten Produced by Electron Beam Additive Manufacturing

Abstract

Due to their superior high-temperature thermomechanical capabilities, sputter erosion durability, and excellent resistance to hydrogen isotopes, tungsten materials have garnered significant interest in fusion nuclear applications. However, low room-temperature ductility and complex machining strategies present significant challenges for traditional fabrication. Electron beam powder bed fusion (EB-PBF) shows promise in manufacturing pure tungsten via high thermal energy input, elevated build temperature, and a tightly controlled high-vacuum environment. This work explores the process, structure, and property relationship of pure tungsten fabricated by EB-PBF, where 99.8% relative density was achieved with reduced cracking by isolating the build substrate and optimizing the print parameter suite. Optical and electron imaging revealed that the microstructure contained equiaxed grains along the build direction, with subgrains present in all inspected grains. Flexural testing at ambient and elevated temperatures demonstrated high ductility at 900°C and flexural strength of 470 MPa at room temperature of additively manufactured tungsten.

Advancements and Perspectives in Additive Manufacturing of Tungsten Alloys and Composites: Challenges and Solutions

“…Over the past decade, extensive research has been undertaken on the AM of unalloyed and alloyed W, as well as W-matrix composites [43,44]. Most studies on unalloyed W have utilized laser powder bed fusion through selective laser melting (LPBF-SLM) [32,[36][37][38]40,43,, and electron beam melting (EBM) [52,53,66,[78][79][80][81][82][83][84][85][86][87][88] of W. Other notable methods employed include laser-direct energy deposition (L-DED) [26,53,66,[78][79][80]89], wire arc additive manufacturing (WAAM) [90], the emerging laser melting deposition [91][92][93][94][95][96][97], and the binder jetting additive manufacturing (BJAM), which shows immense promise for W-based materials [98][99][100][101][102]. Other novel methods such as ultrashort-time liquid phase sintering (LPS) [103], and bound metal deposition (BMD) have also been introduced …”