Friction Stir Processing of Cast Superalloys

This SBIR effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for producing affordable near net shape components made from high performance Ni-based superalloys. Sand casting is a relatively inexpensive casting method not traditionally used to manufacture superalloy castings. Instead of expensive "invested" ceramic shells found in investment casting, the molds are produced from a mixture of inexpensive fine sand and/or graphite powder. Friction stir processing is an emerging microstructural modification technique based on friction stir welding (FSW). It can be applied to enhance the microstructure-properties of the cast material thus improve the damage tolerance capabilities. This step is needed to allow cast superalloy rocket propulsion components to be used without casting factors. If this unique technology can be successfully developed and applied, it will have the tremendous potential for reducing the weight and cost of Ni-based superalloy castings that are used in industries as diverse as rocket propulsion, aircraft engines, land-based gas turbines, and chemical process industry pumps and valves.