Toughness and microstructure of tungsten fibre net-reinforced tungsten composite produced by spark plasma sintering

To enhance the toughness of tungsten based on the extrinsic energy dissipation mechanism, tungsten fibre net-reinforced tungsten composites (W/Wf) containing different tungsten fibre net layers were produced by spark plasma sintering method (SPS). The number of tungsten fibre net layers is 2, 4, 6, and 8, corresponding to a fraction of tungsten fibres as 11.35, 23.90, 32.78, and 39.75 wt%, respectively. The relative density of all SPSed samples is as high as 96.3-98.1% depending upon the fibre content. Close integration at low fibre content but a few voids at higher fibre content were detected between the fibres and matrix. Tensile tests indicate that the plasticity of W/Wf composites is higher than that of pure tungsten, which can be ascribed to the fibres pullout, interface debonding, and plastic deformation of fibres. In particular, the composite with four layers of tungsten fibre net exhibits the largest plasticity owing to the good bonding between the fibres and matrix.