Effect of the W-W contiguity on conductivity of W-Cu composite using the Voronoi diagram

Abstract

W- 15wt.% Cu nanocomposite powder samples were fabricated by ball-milling and subsequent hydrogen-reduction. The powder samples were heated to 1200 degrees C at 5 and 20 degrees C min(-1) and sintered for 1 h to obtain different sintered microstructures. The homogeneity of the sintered microstructures was evaluated by the standard deviation of the Vickers hardness. The W-W contiguity was calculated by using Voronoi diagrams. The sintered microstructure in case of the 20 degrees C min(-1) sample was more homogeneous and had lower W-W contiguity than the 5 degrees C min(-1) sample. The microstructural homogeneity was directly related to the W-W contiguity. Thermal conductivity of the 20 degrees C min(-1) sample was about 5% higher than the thermal conductivity of the 5 degrees C min(-1) sample. This indicates that the thermal conductivity is affected by the W-W contiguity resulting from the homogeneity of the sintered microstructure.