Particle size effect in granular composite aluminum/tungsten*

Compressive dynamic strength and fracture pattern of high density Al-W granular composites with an identical weight ratio between Al (23.8 wt{\%}) and W (76.2 wt{\%}) and with different porosities, size and shape of W component were investigated at strain rate 0.001 1/s. Samples were fabricated by Cold Isostatic Pressing. It was shown that dynamic strength (107 MPa) of composites with fine W particles ($<$1 micron) was significantly larger than strength (73 MPa) of composite with the course W particles (-325 mesh) at the same porosity 26{\%}. More dense samples (porosity 15{\%}) with course W particles exhibited higher strength of 175 MPa. Morphology of W inclusions had a strong effect on dynamic strength. Samples with W wires arranged in axial direction (diameter 100 microns) and porosity of the sample 16{\%} with the same volume content of components demonstrated dynamic strength of 350 MPa. Dynamic strength and fracture pattern of composites was numerically simulated using computer code Raven.