Enhancement in the microhardness of arc plasma melted tungsten carbide

Microhardness is found to increase significantly in arc plasma melted tungsten carbide. To understand the mechanism for such increase, tungsten carbide powder was mixed with tungsten metal powder to prepare mixtures of seven different compositions. The mixtures with varying WC/W ratio were pelletized and melted in an arc plasma followed by cooling in the furnace. It is observed that microhardness value enhances in the product when WC/W2C ratio becomes high. Based on our microstructural finding of [100] WC hard faces and lamellar/acicular structures (due to martensite transformation) carried out by XRD, optical microscope and SEM, an attempt has been made to understand the reason behind the enhancement in microhardness. (C) 2003 Kluwer Academic Publishers.