Effect of cyclic heat treatment and swaging on mechanical properties of the tungsten heavy alloys

A tungsten heavy alloy containing cobalt and molybdenum was subjected to thermo-mechanical processing that employed cyclic heat treatments in order to explore the possibility of enhancing mechanical properties. The alloy was synthesized by liquid phase sintering followed by heat treatments which consisted single as well as multiple cycles. Subsequently, these were subjected to warm swaging imparting about 30% deformation. Discernible changes were observed in the microstructure following cyclic heat treatment in both heat treatment and swaged conditions. While there was marginal increase in tensile properties, impact toughness showed significant enhancement. A detailed analysis of microstructure and fractographs was undertaken in order to understand the reasons for the enhancement in impact toughness and also the implication of these results in the development of heavy alloys with improved properties.