Microstructure and Mechanical Characteristics of WC-3 wt% (Ni, Fe) Hard. Materials by Spark Plasma Sintering for Friction Stir-Processing Tool Applications

In this study, the microstructure and mechanical characteristics of WC-3 wt% Ni and WC-3 wt% Fe hard materials by spark plasma sintering (SPS) for friction stir-processing tool applications were evaluated. Sintered bodies with a diameter of 66 mm were fabricated with a relative density up to 99% after the simultaneous application of a pressure level of 60 MPa and electric current for 35 min mostly without grain growth during sintering. Only the initial phase existed in the initial powers and in the ball-milled powders, but the phases of W2C and WC1-x in all sintered bodies appeared after the sintering process. The Vickers hardness and fracture toughness of the WC-3 wt% Ni hard material were approximately 2,240 kg/mm(2) and 9.1MPa m(1/2), respectively, while those of the WC-3 wt% Fe sintered body were correspondingly 2,242 kg/mm(2) and 6.8 MPa m(1/2).