Huaguo Tang

Preparation and mechanical properties of bulk ultrafine (W0.5Al0.5)C0.65 with minor Fe binder by reactive hot-pressing

ABSTRACT Binderless (W0.5Al0.5)C0.65 produced by reactive hot-pressing (RHP) has high hardness but low bending strength and fracture toughness. In this work, bulk ultrafine (W0.5Al0.5)C0.65 with minor addition of Fe as the binder phase has been prepared by RHP. Rapid synthesis and high densification can be achieved for the (W0.5Al0.5)C0.65 with 0.4–1.0 wt-%Fe by RHP at a relatively low temperature. Pure (W0.5Al0.5)C0.65 without sub-carbide phase or brittle η-type phase can be synthesised due to the fact that the carbon vacancy in (W0.5Al0.5)Cy can reach 50%. And thanks to the combined effect of nanoscaled initial powders, low temperature, rapidly reactive sintering and pressure, bulk ultrafine (W0.5Al0.5)C0.65-Fe with a grain size of about 0.2 μm can be obtained by RHP. Thus, with an appropriate amount of Fe (about 0.8 wt-% in this work), the bending strength and fracture toughness of (W0.5Al0.5)C0.65 can be highly improved.