NOVEL PROCESSING OF CO-CONTINUOUS ALPHA-ALUMINA/BETA-NICKEL ALUMINIDE COMPOSITE STRUCTURES

BFD, Inc. proposes to develop the necessary technology for the in-situ fabrication of near net-shape composite structures comprised of alpha-Al203 and beta-NiAl. Based upon BFD's patented and propriety Co-Continuous Ceramic Composite (C4) technologies, a number of processing routes are proposed including Reactive Infiltration of Shaped Precursors (RISP), High Temperature Solvent Exchange (HTSX), and Minority Species Transformation (MST). It is anticipated that alpha- Al203/Beta NiAl C4 materials will feature a reduced density, increased toughness, and excellent creep resistance as compared to monolithic beta-NiAl. Furthermore, since the prosed processing approaches are in-situ, fabricaton is simplified, eliminating the handling, distribution, and lay-up of costly, delicate fibers typically associated with composite processing. While each of the proposed routes is potentially capable of prong C4 materials of the desired constituents, experimental evidence suggests that the physical and mechanical properties of the structures varies with fabrication route. Thus, the goals of the Phase I effort are to (1) identify suitable processing routs for the desired materials, (2) fabricate test specimens from each processing route, and (3) mechanically and microstructurally characterize statistically significant samples from each of the processing routes.