Abstract:A new NiCu alloy was developed and utilized as binder phase for WC composites. The composites with spherical cast WC particle contents of 55-65 wt.% were prepared by rapid hot-pressing technique. The microstructures were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The results reveal that the cast WC particles are uniformly dispersed within the NiCu matrix. The interface between WC and NiCu alloy is clear with no additional phase observed. Mechanical properties testing indicates that the hardness of the composite shows minimal variation as the cast WC particle content increases. Both the transverse rupture strength (TRS) and fracture toughness show a comparable decline, while the impact toughness first increases and then decreases. The NiCu alloy matrix plays a critical role in enhancing the fracture toughness of the composite. However, at high strain rates, the impact toughness deteriorates due to strain rate hardening of the NiCu matrix and a reduced density resulting from the higher WC content.

Key words: rapid hot-pressing; WC composite materials; NiCu alloy; toughness