Titanium Brazing for Structures and Survivability

Titanium is a candidate as a structural material for all new tactical and armored ground vehicles, because of its high strength-to-weight ratio, excellent corrosion resistance, and inherent ballistic resistance. However, titanium as a structural material is much less mature than both steel and aluminum alloys, especially in the area of joining. While welding is the typical joining method for titanium, vacuum brazing is an option in areas that are difficult to access for welding as well as areas near other nonmetallic materials, such as ceramics. This work focuses on vacuum brazing of titanium (both Ti-6Al-4V and commercially pure titanium) and the effect of processing changes (alloy, temperature, pressure), including post-braze hot isostatic pressing, on mechanical properties and microstructure. This study will examine the joining of both plate materials as well as lightweight, periodic pyramidal core structures. Shear and tensile testing is performed to determine the strength/ductility relationship to the various processing routes. Microscopy (optical and SEM) is employed to quantify the degree of bonding and to examine the microstructural changes, both within the base materials and at the bond line, associated with the process variations.
The original document contains color images. Reprint from the Proceedings of the 3rd International Brazing and Soldering Conference, p268-273, San Antonio, TX, 24-26 Apr 2006.