Size effects on the deformation behaviour of W–Cu composites under shear loading

Abstract

Tungsten/copper (W/Cu) particle reinforced composites were used to investigate the scaling effects on the deformation behaviour under shear loading. The effects of the deformed volume on the degree of deformation and on the fracture behaviour were studied. W/Cu-80/20, 70/30 and 60/40wt.% each with tungsten particle sizes of 10μm and 30μm were tested under shear loading using axis-symmetric hat-shaped shear specimens with different shear zone widths. The mechanical tests were done at different shear strain rates (dγ/dt=0.01s−1, 1s−1 and 100s−1) and temperatures (T=20–800°C). Clear scaling effects in terms of high stress level, higher strain up to fracture and shear localization were observed in shear specimens with a small shear zone width. Strain rate sensitivity was determined at higher strain rates. The development of deformation and damage within the shear zone was followed by step loading and FE-simulation. The FE-simulation was done on the real microstructure of the whole shear zone. The results of the FE-simulation were comparable with the experiment.