Tensile behavior of hybrid tungsten composites with zirconium carbide nanoparticles and tungsten fibers

Hybrid tungsten composites reinforced with zirconium carbide (ZrC) nanoparticles and tungsten fibers were developed by the conventional powder metallurgy process (ball-mill mixing of powders and fibers followed by spark plasma sintering). The synergistic and mutual influences of the fibers and nanoparticles on tungsten were investigated in tensile behavior and fracture-energy tests. Aided by the ZrC nanoparticles, up to 30% of the fibers could be embedded in the tungsten matrix. The fracture energy was maximized by co-introducing 0.2 wt% ZrC particles with 20 wt% short tungsten fibers. The fracture-energy enhancement of the short fibers is contributed by pseudo-toughness from the fiber–matrix interface, inherent toughness from the fibers themselves, and grain refinement (by 50%) of the tungsten matrix. The fracture energy of the composite is very sensitive to the ZrC content, because the two-way action of ZrC weakens the pseudo-toughness of the interface energy.