Investigation on the characteristics of micro- and nano-structured W-15 wt.%Cu composites prepared by powder metallurgy route

The properties of W-15 wt.%Cu composites were investigated by preparing two distinct composites of micrometer and nanoscale structures. Micrometer composite was produced by mixing elemental W and Cu powders and nanometer one was synthesized through a mechanochemical reaction between WO(3) and CuO powders. Subsequent compaction and sintering process was performed to ensure maximum possible densification at 1000-1200 degrees C temperatures. Finally, the behavior of produced samples including relative density, hardness, compressive strength, electrical conductivity, coefficient of thermal expansion (CTE) and room temperature corrosion resistance were examined. Among the composites, nano-structured sample sintered at 1200 degrees C exhibited better homogeneity, the highest relative density (94%) and mechanical properties. Furthermore, this composite showed superior electrical conductivity (31.58 IACS) and CTE (9.95384x10(-6)) in comparison with micrometer type. This appropriate properties may be mainly attributed to liquid phase sintering with particle rearrangement which induced by higher capillary forces of finer structures. (C) 2011 Elsevier Ltd. All rights reserved.