Improving the damage potential of W-Zr reactive structure material under extreme loading condition

Projectiles made of reactive structure materials (RSM) can damage the target with not only kinetic but also chemical energy, but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached. In this work, a ductile coating of Ni was introduced to a tungsten-zirconium (W-Zr) alloy, a typical brittle RSM, to preserve the damage potential of the projectile. Detonation driving tests were carried out with X-ray photography and gunpowder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples, respectively. The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction. The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions, whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving. The crack propagation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile. Specifically, the Ni coating envelops the W-Zr core until the coated sphere penetrates the target, and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.