Influence of deformation ratio on microstructure and adiabatic shear banding in tungsten heavy alloy processed by rotary swaging

The as-sintered 93W-4.9Ni-2.1Fe alloy was processed by rotary swaging with various deformation ratios. The effect of deformation ratio on the microstructure and adiabatic shear localization were investigated. The microstructure examination showed that the tungsten particles were elongated along the deformation direction in the rotary swaged tungsten heavy alloys (WHAs) and the aspect ratio of tungsten particles increased from 1.32 to 2.41 with the deformation ratio rising from 3.45% to 42.11%. At the same time, the matrix between tungsten particles was elongated to be strip gradually with the increasing deformation ratio. The dynamic compression result of radial specimens revealed that when the deformation ratio got to 15.84% (aspect ratio of tungsten particles was 1.47), the plastic deformation mode changed and adiabatic shear banding began to occur in rotary swaged WHAs. With the rising deformation ratio (or aspect ratio of tungsten particles) in swaged WHAs, the width of adiabatic shear banding reduced and the sensitivity to adiabatic shear banding of radial specimen increased. Moreover, with the increase in deformation ratio, the strain hardening capability of the alloys reduced, and the adiabatic temperature rose during dynamic compression increased which led to the more apparent softening effect. These were the main reasons why the sensitivity of the rotary swaged WHAs to adiabatic shear banding increased with the rising deformation ratio.