Reactive Multilayer Joining of SiC and Ti

The drive to develop the Future Combat System requires improved methods for bonding SiC armor to Ti-6-4 structures. Current methods that utilize epoxy adhesives provide limited strength and ballistic performance. Reactive multilayer joining offers thenovel ability to form strong metallic joints between SiC tiles and Ti-6-4 plates, at room temperature and in air. We have demonstrated this ability in our Phase I project, and we have also shown that the resulting joints have the desired shear strength of52 MPa, twice that of epoxy joints.In the proposed Phase II project we will refine the reactive joining process and demonstrate that arrays of SiC tiles can be bonded onto Ti-6-4 plates with the desired ballistic and physical properties. Specifically, we will (1) optimize the reactivejoining process by varying the brazes on the Ti plates, the pressure applied during joining and the roughness of the braze surfaces; (2) establish the ballistic superiority of the reactive bonded SiC-Ti joints over current epoxy-based SiC-Ti joints; and(3) demonstrate that the reactively bonded SiC-Ti joints meet all the relevant military specifications for armor joining.The most direct benefit is the enhanced ballistic performance of SiC armor on Ti-6-4 military vehicles. By doubling the bond strengthcompared to epoxy, dramatic improvements in ballistic performance are expected. More generally, demonstrating and optimizing the ability to reactive join ceramics to metals will aid all armor mounting programs, including the mounting of alumina toaluminum. Lastly, the ability to bond ceramics to metals will also benefit many other defense and civilian applications where the benefits of ceramics are desired but the means for bonding them is limited.