The effect of HfC content on mechanical properties HfC–W composites

• The effect of HfC on mechanical properties of W composites was investigated.
• Interdiffusion of Hf and W atoms produced mixed carbide (Hf,W)C.
• Mixed carbide is beneficial for strengthening by forming strong interfacial bonds.
• Outstanding improvements of mechanical properties at RT as well as high temperature
• Mechanical properties improved due to effective load transfer from W matrix to HfC.

For improving the mechanical properties of tungsten, HfC–W composites were fabricated by ball milling and spark plasma sintering process. The microstructure and mechanical properties of the composites were investigated. The interdiffusion of the Hf and W atoms during sintering produced a mixed carbide, identified as (Hf,W)C. This interfacial mixed carbide helped in developing a good interface joint with the adjacent W matrix. The increase in mechanical properties of the HfC–W composite at room temperature as well as high temperature was attributed to the reinforcement effect of the HfC particles. One of the strengthening mechanisms of the composite can be attributed to the formation of mixed carbide (Hf,W)C by interdiffusion at the interface, which assured the effective load transfer from the W matrix to the hard HfC particles.