Fiber Volume Fraction Influence on Randomly Distributed Short Fiber Tungsten Fiber-Reinforced Tungsten Composites

Abstract

For future fusion reactors, tungsten (W) is currently the main candidate for the application as plasma-facing material due to its several advanced properties. To overcome the brittleness of W, randomly distributed short W fiber-reinforced W (Wf/W) composites have been developed using field-assisted sintering technology (FAST). Herein, Wf/W materials with different fiber volume fraction (20–60%) are manufactured by FAST process to study the fiber volume fraction influence on the composite properties. Wf/W with ductile fibers and brittle fibers is produced using different tool setups during the production. Three-point bending tests on prenotched samples, 4-point bending tests, and tensile tests have been performed to determine the fracture behavior and flexural/tensile strength of the material. Wf/W materials with 30–40% fiber volume fraction exhibit a promising pseudoductile behavior, similar to fiber-reinforced ceramic composites. However, Wf/W with 20% and >50% fiber volume fraction shows only a limited extrinsic toughening effect. In terms of flexural strength, with increasing fiber volume fraction, the tensile/flexural strength does not show a clear increasing tendency, or even lightly decreases.