Scalling effects on the deformation behaviour of W/Cu composite materials under dynamic loading

Abstract

Tungsten/copper (W/Cu) particle composites were used to investigate the scaling effects on their deformation and fracture behaviour. The effects of the volume fraction and the particle size of the reinforcement (tungsten particles) were studied. W/Cu-80/20, 70/30 and 60/40 wt.% each with tungsten particle size of 10 and 30 μm were tested under compression loading up to high strain rates. Cylindrical compression specimens with different volumes (Do = H 0 ) were investigated with strain rates between 0.001s -1 and 6000 s -1 at temperatures from 20°C to 800°C. A clear dependence of the flow stress on the deformed volume of the specimens was shown for compression loading. An extensive metallographic investigation was carried out to determine a correlation between the deformation of the tungsten particles and the global deformation of the specimen. The contribution of the hard phase in the deformation process has shown to have an effective influence in the deformation process. The size of the deformed zone under compression loading showed an effect on the failure mechanism. The material behaviour of the different W/Cu composites was described with material laws. The parameters of the material law were presented as a function of the strain rate, temperature, the volume fraction and the particle size of the tungsten. The mechanical behaviour of the composite materials was numerically computed with the previously determined material laws.