Fabrication of fine-grain tungsten heavy alloy and its dynamic failure behavior

Fine-grain(FG) 93W-4.9Ni-2.1Fe alloy containing 0.03%Y2O3(mass fraction) was obtained via liquid phase sintering of nano-composite powders prepared by spray drying,subsequent thermal reduction process.The influence of Y2O3 on sintering behavior and microstructure and the dynamic mechanical properties and dynamic failure were studied.The results show that the near full densification is realized and the finer spherical-shape tungsten grains with the size of about 5 μm in the alloy are obtained during liquid phase sintering in the range from 1 380 ℃ to 1 410 ℃,which is 120 ℃ lower than that of the traditional tungsten heavy alloys,and the relative density of the alloy reaches over 99%.Compared with traditional tungsten heavy alloys,the fine-grain tungsten heavy alloy possesses higher yield strength and larger elongation at high strain rate,and promotes the tendency to adiabatic shear band(ASB) formation at lower strain rate.On the basis mentioned above,adding Y2O3 can further increase the sensitivity of ASB of fine-grain W-Ni-Fe alloy,which is more beneficial to form obvious ASB at lower strain rate.