Microstructure and Dynamic Mechanical Properties of Extruded Tungsten Alloy Rods by Microwave Sintering

The dynamic mechanical properties of 93W-4.9Ni-2.1Fe alloy rod by microwave sintering were investigated under dynamic compression using Split Hopkinson Pressure Bar. The microstructure and micro-hardness of the samples after dynamic compression were analyzed and tested by Scanning Electron Microscope (SEM), Optical Microscopy(OM) and Ultra Nano Hardness Tester (UNHT). The results show that tungsten grains and binder phase of the microwave sintered alloy deform uniformly during impact compression. When the strain rate is 2200 s(-1), the stress of 93W-4.9Ni-2.1Fe alloy is 2587 MPa, and micro-hardness of tungsten grains and binder phase are 8.716 GPa and 6.267 GPa, respectively. When the strain rate is 2200 s(-1), a thermal softening effect is formed due to binder phase deformation, and the adiabatic shear band pears along 45 with the direction of the impact force. Within the center of the bands, the tungsten grains are severely elongated to be fibrous along the propagation directions of the adiabatic shear bands.