Porous Tungsten Synthesized Via Dealloying: Fe6w6c Induced Structure Modification and Mechanical Behavior

Porous tungsten with high strength is required in the nuclear industry. However, porous metals prepared by dealloying suffer from grain boundary separation and poor connectivity of the generated ligament structure, resulting in limited strength. This work synthesized porous tungsten with high strength by dealloying with Fe6W6C as the bonding phase. The sintering temperature of the precursor and C content on the Fe6W6C content is investigated, and the effects of Fe6W6C content on the microstructure and mechanical properties of porous tungsten are systematically studied. Fe6W6C can be regulated by precursor sintering temperature and C element. Temperature is the main factor affecting the Fe6W6C content. The ideal W framework is achieved at the sintering temperature is 800 °C when the C addition is 0.1~0.3 wt.% and the amount of Fe6W6C generated is 9.1~27.2 wt.%. After heat treatment, Fe6W6C rearranges under the effect of surface tension and fills into the sintered neck and the gap between the W grain, forming a smooth and continuous W-Fe6W6C composite ligament. The increase of Fe6W6C leads to increased ligament width, reduced “dangling ligaments” and neck curvature, thereby improving the mechanical properties of porous tungsten. The porosity of porous tungsten ranges from 68.1% to 70.6%, and the highest compressive strength is 105 MPa. This work provides a theoretical reference for designing and preparing high-performance porous tungsten.