The effect of sintering temperature on densification of nanoscale dispersed W-20-40%wt Cu composite powders

Nanoscale dispersed particles of W-20-40%wt Cu were synthesized using a chemical procedure including initial precipitating, calcining the precipitates and reducing the calcined powders. The powders were characterized using X-ray diffraction and map analyses. The effect of sintering temperature was investigated on densification and hardness of the powder compacts. Relative densities more than 98% were achieved for the compacts which sintered at 1200 degrees C. The results showed that in the case of W-20%wt Cu composite powders, the hardness of the sintered compacts increased by elevating the sintering temperature up to 1200 degrees C while for the compacts with 30 and 40%wt Cu, the sintered specimens at 1150 degrees C had the maximum hardness value. The microstructural evaluation of the sintered compacts by scanning electron microscopy showed homogenous dispersion of copper and tungsten and a nearly dense structure. A new proposal for the variation of the mean size and morphologies of W-particles with volume percent of copper melt within the composites has been suggested. (C) 2009 Elsevier Ltd. All rights reserved.