Аңдатпа
This study investigates the effect of spark plasma sintering (SPS) temperature (1250 °C and 1300 °C) on the microstructure, phase composition, porosity, density of cobalt-free WC–Fe–Ni, WC–Fe, and WC–Ni hard alloys. The aim of the work was to evaluate the potential of Fe-and Fe–Ni-based binders as alternatives to cobalt in cemented carbides for cutting-tool applications. Microstructural analysis revealed that the WC–Fe–Ni alloy formed a homogeneous and dense structure with a uniform distribution of WC particles at 1250 °C, while increasing the sintering temperature to 1300 °C resulted in carbide grain refinement. In contrast, the WC–Fe system exhibited grain coarsening at the higher temperature. The WC–Ni alloy was characterized by large irregular grains and the formation of brittle secondary phases. X-ray diffraction analysis confirmed the presence of WC, Fe3W3C, FeNi3, and Fe–Ni solid-solution phases in the WC–Fe–Ni system, whereas the WC–Ni alloy was dominated by W2C and W3Ni3C phases. Increasing the SPS temperature reduced porosity from 13.2% to 12.7% in WC–Fe–Ni and from 13.8% to 12.0% in WC–Fe, accompanied by an increase in relative density to approximately 87–88%. In contrast, the WC–Ni alloy exhibited the highest porosity (~16%). The results demonstrate that both binder composition and SPS temperature strongly influence phase evolution, densification, and microstructural development. Fe-containing binders provided greater structural homogeneity and phase stability, highlighting their potential as cobalt-free alternatives for cemented carbide applications.