CASTABLE REFRACTORY INVESTMENT MOLD MATERIALS AND METHODS OF THEIR USE IN INFILTRATION CASTING

摘要

Disclosed are methods and materials for preparing investment molds useful in pressure infiltration casting of near net-shape metal or metal matrix composite (MMC) components. One embodiment of the invention includes disposing a slurry (30) of an appropriately sized refractory material and a vehicle around a preform (10) or fugitive pattern, removing the bulk of the vehicle, then curing/drying the refractory material to create an investment mold of the invention. Subsequently, pressure infiltration casting with a molten infiltrant (52) using the investment mold (44') permits infiltration of the mold cavity and/or preform without infiltration of the investment mold (44'). As a result, the investment mold readily is removed to provide the near net-shape metal or MMC component. In other embodiments of the invention, a non-fugitive pattern is used, typically with a modified refractory cement of the invention. In these embodiments, the non-fugitive pattern is removed after formation of the investment mold to provide a suitable mold cavity which may be used to produce near net-shape metal or MMC components.