The deformation and fracture mechanism of tungsten alloy under different strain rates

Three loading modes of quasi-static, Hopkinson dynamic compressing and explosive loading were used to study the deformation and fracture mechanism of tungsten alloy with 97.5% tungsten content in this research work. The results show that, under the quasi-static compressing, a large number of tungsten particles are elongated at the 45° directions with the axial direction and the cleavage fracture occurs in the radial direction. While under dynamic compressing with 10³ s^-1 strain rate, the localized shear occurs at the 45° direction with the axial direction, the tungsten-tungsten fracture and the tungsten particle cleavage fracture also occur at the radial outer surface of the sample. When the strain rate is up to 10⁵~10⁶ s^-1, the tungsten particles irregularly break to fragments and the strip pattern appears in tungsten particles. At the same time, lots of deformation twins appear as embryonic zone of crack, which increases the cleavage fracture. The pure brittle fracture of tungsten alloy happens under high strain rate loading.