Effect of fibrous orientation on dynamic mechanical properties and susceptibility to adiabatic shear band of tungsten heavy alloy fabricated through hot-hydrostatic extrusion

The tungsten heavy alloys (WHAs) with fibrous grains were obtained by hot-hydrostatic extrusion at 950 °C with plastic deformation ratio of 75%. Dynamic mechanical behaviors under uniaxial dynamic compression were systematically investigated with the angles between the loading direction and the extruding direction being 0°, 45° and 90°. The testing results show obvious difference in dynamic behaviors and susceptibility to adiabatic shear band (ASB) for different specimens. In the 0° specimens, no localized flow is observed. The 45° specimens exhibit slight localized shearing. In the 90° specimens, localized ASB was firstly observed at an angle of 45° with respect to the fibrous orientation followed by cracking, which is greatly desirable for kinetic energy penetration applications. Microstructure analyses reveal that the high susceptibility to ASB of the 90° specimens result from adiabatic temperature rising during dynamic loading and reduced strain hardening caused by the special micro-strained condition and fiber distribution.