Sintering of nanostructured W-Cu alloys prepared by mechanical alloying

NanostructureQ (NS) powders with compositions corresponding to W-20wt%Cu and W-30wt%Cu were prepared by mechanical alloying. The microstructure and grain size of as-milled and annealed powders were analyzed by transmission electron microscopy. The compacted specimens were sintered at temperatures in the range 1000 degrees 1300 degrees and then the microstructures of sintered parts were analyzed by scanning electron microscopy. Sintering of mechanically alloyed W-Cu alloys appears to be independent of Cu content, and may be explained in terms of recovery and grain growth in the mechanically alloyed powders as well as impurity activated sintering of W. After sintering, Cu pools are formed outside the mechanically alloyed powders. A relative sintered density of more than 95% is obtained by particle rearrangement during liquid-phase sintering, and the greatest homogeneity of W and Cu phases is achieved by sintering at 1200 degrees. (C) 1998 Acta Metallurgica Inc.