A simple test to determine the effectiveness of different braze compositions for joining Ti-tubes to C/C composite plates

A simple tube-plate joint tensile test was implemented to compare the effectiveness of commercial brazes, namely, TiCuNi, TiCuSil, and Cu-ABA, used for bonding Ti-tubes to C–C composite plates. The three braze systems yielded different; yet, repeatable results. The Cu-ABA system proved to have about twice the load-carrying ability of the other two systems due to the fact that the bonded area between the braze material and the C–C plate was largest for this system. The orientation of the surface fiber tows also had a significant effect on load-carrying ability with tows oriented perpendicular to the tube axis displaying the highest failure loads. Increasing the process load and modifying the surface of the C–C plate by grooving out channels for the Ti-tube to nest in resulted in increased load-carrying ability for the TiCuSil and Cu-ABA systems due to increased bonded area and better penetration of the braze material into the C–C composite.