Behavior of W-Cu Nanocomposite Fabricated Through Thermochemical Synthesis

In this work, homogeneous thermochemical co-precipitation method was used to fabricate W-25wt%Cu nanocomposite. Synthesized nanocomposite powder was calcined and reduced. A hydrogen atmosphere sintering at 1200oC for 105 consolidated the product up to a density close to 98% theoretical density. Wear experiment were carried out using a pin-ondisc set up at three normal loads of 5, 10 and 15 N and the dissipated energy was calculated in each case as a funsction of wear distance. Evalustion of the slope of the “dissipated enargy-wear distance” plot demonstrated the constancy of this slope at each certain normal load. However, the steepness of this slope, was in direct relation with the magnitude of the normal load (a J/m for 5N, b J/m for 10N and c J/m for 15N), demonstrating the higher potency of larger normal loads for injecting energy and thus, wear damage to the material. According to this constant slope of this plot at each normal load, constancy of the wear mode under each loading condition can be ruled out. Simultaneous consideration of mechanical and microstructural parameters of wear revealed that the dominant wear mode in all loading conditions was fatigue wear and the corresponding active wear process was delamination. Formation of sub-surface cracks and gradual degradation of the worn surface by flaking off, were of importance in the evolution of this type of wear damage.