Studies on directional tungsten-rhenium alloys

KE-projectiles are usually made of uranium or tungsten based alloys. Uranium alloy has better penetration due to the deformation behaviour; it is said to be selfsharpening. To increase the penetration performance of tungsten alloys, two approaches have been proposed: "flow-softening" and "flow-anisotropy". The latter is based on the production of an anisotrop alloy with directionally oriented tungsten crystals, where the deformation behaviour changes depending on the orientation. An investigation of directional tungsten-rhenium alloys with potential as a projectile material has been done. The investigated materials have rhenium contents up to about 5% and the grains are oriented along the [100]- or [110]-axis. Mechanical experiments at strain rates up to 1 s-1 and temperatures from 20 to about 800 °C have been done. The results from the mechanical testing in elevated temperatures show that samples with a [100]-axis parallels with the loading direction have a lower fracture strain than corresponding [110]-oriented material. At room temperature fracture occurs at low strain with seemingly no prior plastic deformation independent of strain rate and material. The result from the metallographic investigation in a scanning electron microscope show that the fracture surfaces have a more ductile appearance with increasing rhenium content.