Explosive Bonding of Refractory Metal Liners

Many of the U.S. Army's gun tubes are currently electrolytically plated with chromium in order to extend their service life. In order to eliminate the hexavalent chromium used in the plating process, the development of explosively bonded refractory metal liners has been carried out. While the ultimate application of this technology is for large caliber cannons, the Bushmaster 25-mm M242 medium caliber cannon has been used as a test bed to save costs. A vendor was selected who could explosively bond refractory metals to a short section of a gun tube. The quality and strength of these bonds have been assessed in several ways. Visual observation of sectioned gun tubes showed good liner adhesion to the gun tube. Shear strength tests have been conducted on several bonded liners. Finally, hot hardness tests have been conducted on three explosively-bonded liners. These tests led to the decision to select Ta-10W as the liner material. The vendor was able to explosively bond a Ta-10W liner to a full-length M242 ba...