Ductile Intermetallic Joining for Heavy Alloy

Good ballistic performance results when the maximum kinetic energy is delivered tothe target. Increasing the weight of the projectile achieves this goal. Onereasonable way to enhance the mass behind the nose of the penetrator is to augmentits size. The conflict between increased lethality for large projectiles and limitedfacilities for producing large penetrators leads to a need to join small pieces ofheavy alloy into larger projectiles.A copper joint is not strong enough. Nickel bonding would require a high processing temperature, which would cause grain coarsening and lower strength.A better joining method uses an interlayer that reacts to create a ductile intermetallic compound. Good adhesion is achieved during the temperature transient associated with the bonding but the reaction temperature must be held below the eutectic point ofthe Ni-Fe-W matrix to minimise grain growth. Titanium nickelide, alloyed aluminium nickelide and titanium aluminide have enough tensile strength and ductility to meet the requirements of military projectiles. Corrugating the junction surface area will increase further the strength of thebonding.Using ductile intermetallic compounds as bonding interlayers will lead tostrong joints for tungsten heavy alloy parts that will make possibleproduction of full-scale penetrators for military needs, and larger parts forcivilian use (radiation shields, gyroscope components etc.)