Nanostructured bulk novel hard material with “rounded” grains obtained by nanocrystalline “rounded” (W0.5Al0.5)C powders

A novel nano-scaled bulk hard material (W0.5Al0.5)C–Co with “rounded” grains was prepared by nanocrystalline “rounded” (W0.5Al0.5)C powders with “rounded” particle shape in this study. The nano-scaled “rounded” particles do not contain sharp edges, which form local tensile stress concentrations on loading of the composite, thus leading to improved toughness and reduced sensitivity to crack. Nanocrystalline (W0.5Al0.5)C powders with “rounded” particle shape were used as starting materials. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to characterize the samples. The novel hard material has superior mechanical properties; it possesses high hardness (25.36 GPa), high bending strength (2213 MPa), and lower density (9.360 g cm−3) compared with the common hard material (WC–Co). The formation mechanism of the “rounded” (W0.5Al0.5)C particles, and the relationship of the mechanical properties and the microstructures are also discussed.