%0 Journal Article
%T Effect of Heating Mode and Copper Content on the Densification of W-Cu Alloys
%A Avijit Mondal
%A Anish Upadhyaya
%A Dinesh Agrawal
%J Indian Journal of Materials Science
%D 2013
%R 10.1155/2013/603791
%X This study investigates the effect of heating mode on the sintering of tungsten-copper alloys containing up to 30£¿wt.%£¿Cu. The sinterability of the W-Cu system consolidated in a 2.45£¿GHz multimode microwave furnace has been critically compared with that processed in a radiatively heated (conventional) furnace. The as-pressed W-Cu alloys can be readily sintered in microwave furnace with substantial (sixfold) reduction in the processing time. As compared to conventional sintering, microwave processing results in greater densification, more homogenous distribution of the binder phase, and smaller tungsten grain size. The densification in compacts increases with increasing Cu content. For all compositions, the electrical conductivity and hardness of microwave sintered W-Cu alloys are higher than those of their conventionally sintered counterparts. This study investigates the effect of heating mode on the sintering of tungsten-copper alloys containing up to 30£¿wt.%£¿Cu. The W-Cu alloys were sintered in a 2.45£¿GHz microwave furnace with substantial (sixfold) reduction in the processing time. As compared to conventional sintering, microwave processing results in greater densification, more homogenous distribution of the binder phase, and smaller tungsten grain size. This results in higher electrical conductivity and hardness of the microwave sintered W-Cu alloys. 1. Introduction Tungsten-copper alloys are widely used for a range of applications, such as electrical contact materials, thermal-management devices, and in ordnance applications [1¨C3]. On account of the refractoriness of the major phase ( : 3420¡ãC), these alloys are usually processed through liquid phase sintering [4]. Due to lack of solubility between W and Cu, it is rather difficult to attain full densification in this system. For ensuring complete densification through liquid phase sintering, sufficient amount of melt and its homogeneous distribution are required [5]. Unfortunately, due to the density difference between the constituents, it is rather difficult to ensure Cu homogeneity. Thus, the W and Cu powders are often comilled, which, in turn, results in contamination from the milling media and results in subsequent degradation of property, such as conductivity [6]. Alternatively, Cu coating over the tungsten has shown to enhance densification during sintering [7]. However, such a technique is not economically viable for upscaling. Another approach for ensuring densification in the W-Cu system is through the addition of transition metal additives that activate the sintering kinetics [8¨C10].
%U http://www.hindawi.com/journals/ijms/2013/603791/