A Novel Integrated Non-Parasitic Nb Alloy – Based Structure for High Temperature Applications

There is a strong need for producing novel aeroshell structures that integrate the thermal protection system with the airframe and to utilize new lightweight materials that possess the requisite high temperature strength and performance such that future hypersonic vehicles are operationally responsive to increasing demands of robustness and high reliability. In this proposal, this aim is directly addressed by a multi-pronged approach of utilizing a ceramic-coated low-density Nb alloy together with studies on joining it with graphitic foam and a substrate material such as titanium alloy. Such a carefully tailored integrated thermal protection system is inherently non-parasitic and is expected to experience very low thermal stresses and have high resistance to thermal fatigue. The main focus during the Phase I program will be in the demonstration of processing ductile Nb alloys as thin sheets and successful application of YAG on the alloy surface and assessment of the reliability and performance of this material. Studies on the high temperature mechanical properties of the Nb alloy and the oxidation resistance of the YAG-coated Nb alloy will be systematically investigated. Subsequently, preliminary experiments on joining this composite to graphitic-foam will also be carried out.