The effect of microstructural aspects of W-Cu composites on electrical conductivity and thermal erosion

Molten copper infiltration through tungsten skeleton produces W-Cu composites with versatile applications. In this research, the compressibility and sintering of three W powders with different particle sizes (fine: 1.2 mu m, medium: 6 mu m, coarse: 8.5 mu m) were studied, and 80 vol%W composite specimens were produced from the various primary tungsten powders. The microstructure and electrical conductivity of composites were examined, and a model was successfully developed to establish a relationship between microstructural aspects and electrical conductivity. In addition, the W-Cu composites were exposed to a high-velocity oxyacetylene flame to evaluate the thermal erosion resistance. Results showed that in addition to density, microstructural aspects have significant effects on conductivity and thermal erosion resistance of W-Cu composites. The larger copper channels in W-Cu composites provided higher conductivity and also higher erosion resistance. In addition, the uniformity of channels walls had the same effects. These microstructural aspects affected on evaporation of the copper phase and the transpiration cooling.