Microstructure and high temperature mechanical properties of advanced W–3Re alloy reinforced with HfC particles

W–3Re alloys reinforced with various HfC particles contents (0 wt%, 0.5 wt%, 1 wt%, 5 wt%, 10 wt%) were fabricated using spark plasma sintering (SPS) at 2050 °C for 10 min. Microstructure, Vickers hardness and high temperature compression properties of the sintered W-3Re-xHfC alloys were investigated. Spherical HfC nanoparticles and micron scale clusters are distributed at the grain boundaries of the W–Re matrix. These nanoscale HfC particles pin dislocations and grains boundary as well as refine grain, thus enhancing the strength of composites. Furthermore, the HfC-W interfaces are well bonded semi-coherently without apparent interfacial gaps. The high temperature strength and micro-hardness of sintered composites are significantly increased with an increase of HfC contents. The micro-hardness of W–3Re alloy was 659.4 HV when 10 wt % HfC was added, which is enhanced up to 92.5 % compared with matrix. Its compressive strength is 850 MPa, increased by ~286 % compared with that of W–Re matrix. Quantitative analysis indicates that the main strength mechanisms are grain refinement, Orowan strengthening and interfacial thermal mismatch strengthening, which are influenced significantly by the HfC contents. This study provides new insights into composites performance optimization, reinforcement designs and strengthening mechanisms of particles reinforced W matrix alloys.