Mechanical properties of tungsten heavy alloy and damage behaviors after hypervelocity impact

Abstract

Abstract 93W‐4.5Ni‐1.5Fe‐1Co (W) was prepared by powder metallurgic method, and then dynamic mechanical properties of this material were tested at high temperature by means of high‐temperature split Hopkinson pressure bar (SHPB). The results show that the material possesses high‐dynamic mechanical properties, significant temperature effects, and strain hardening behaviors. Used two‐stage light gas gun, the penetration test of 93W projectile was finished. After the completion of the test, through the microstructure observation of the residual 93W projectiles with the aid of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it can be found that there are obvious signs of hot melt existing on the surface of the projectile, a lot of adiabatic shear bands inside the projectile, and microcracks exist at the end of adiabatic shear bands. The test results show that adiabatic shear is the main form to cause the projectile failure and it is the emergence of the adiabatic shearing phenomenon that makes 93W display good self‐sharpening property in the process of hypervelocity penetration. At the same time, the results of TEM observation show that there are high‐density dislocations at the interface between W and Ni–Fe–Co‐based alloy inside the 93W.