Characterization of tungsten fragmentation in a W-25%Cu composite after high-pressure torsion

A coarse-grained W-25%Cu alloy with a tungsten particle size of 2-10 mu m is subjected to severe plastic deformation by high-pressure torsion at different temperatures. The evolution of the microstructure with increasing strain is investigated. It is shown that high-pressure torsion deformation causes a strong refinement of tungsten particles. It is found that the tungsten particle fragmentation during high-pressure torsion follows the fractal distribution and demonstrates a multi-fractal behavior. Similarity of this fragmentation process with fragmentation observed in nature at the macro-, micro-, and nano-levels is discussed. (c) 2006 Elsevier Inc. All rights reserved.