Enhanced mechanical properties of WC-15NiTi alloy via NiTi solid solution binder: A breakthrough in cemented carbides

To overcome the technical limitation of inferior mechanical performance in conventional WC-Ni alloys, a WC-15NiTi alloy exhibiting superior mechanical characteristics was fabricated by employing NiTi solid solution powders as the binder-phase precursor. This research aims to explore how different approaches of introducing Ti affect the microstructural evolution and mechanical behavior of the resulting alloy. Experimental findings indicate that incorporating NiTi solid solution powders can efficiently suppress the abnormal growth of WC grains, markedly reduce the average grain size, and promote a homogeneous dispersion of the bonding phase while avoiding the formation of Ni pool defects. These improvements yield a bending strength of 2804 MPa, a Vickers hardness of 1427 HV₃₀, and a fracture toughness of 14.65 MPa·m¹/², representing increases of 43.5 %, 72.7 % and 12 %, respectively, relative to the Ti-free alloy. Furthermore, the NiTi solid solution phase is predominantly retained within the alloy's microstructure following the sintering process. This contributes to the enhancement of both the structural characteristics and mechanical performance of the material through mechanisms such as solid solution hardening and improved interfacial adhesion with WC particles. The study presents a valuable investigation into the reinforcement and fracture resistance imparted by the solid solution binder phase in WC-Ni composites, shedding light on potential strategies for advancing the design and fabrication of other high-strength metallic ceramics.