Fabrication of High Temperature Metal Matrix Composite Tubes by Vapor Deposition Methods

Advanced turbine engines and flight vehicles will depend upon new, high-temperature metal matrix composites (MMC's) to meet performance goals. Engineering characterization of such materials is difficult and costly, which accounts for the meager property database available to designers. Thin-walled tubes would be especially useful for developing constitutive relations and failure criteria under multiaxial (T-C/Torsion) combined loads (thermal and mechanical, static and dynamic). This project will develop a process for manufacturing and consolidating MMC precursor wire into high quality tublar specimens by hot isostatic pressing. The MMC wire will be fabricated by a physical vapor deposition process which applies diffusion barriers (if needed) and matrix metal onto a continous ceramic monofilament. The wire is a microcomposite of the final structure, carrying precisely the amount of matrix needed to achieve the desired final volume fractions. Phase I will establish the feasibility of this approach to making high temperature MMC thin-walled tubes. Phase II would demonstrate reproducible pilot scale production of high-quality tubes and, in the process, establish protocols for fabricating more complex engineering structures from these new materials.