*** 9760593 Zimmer This Small Business Innovation Research (SBIR) Phase I will explore superplastic forming in composite materials, which are not normally deformable. It is a hot deformation process which requires extensive tensile elongations. In contrast to conventional superplasticity, which relies on a stable fine-grained microstructure, superplasticity in composites arises from internal stresses generated by the volumetric mismatch between a transforming (allotropic) matrix material and a stable, non-transforming second phase. Termed Transformation Mismatch Superplastitity (TMS), the new process uses thermal cycling to attain elongations of more than 200%. Titanium metal matrix (MMC) composites, reinforced with titanium carbide (TiC) and boride (TiB) particulate manufactured by powder metallurgy, are commercial because of improved elevated temperature strength, elastic modulus, and wear-resistance. Phase I will develop methods of rapid thermal cycling and test the superplastic forming limits of titanium-alloy MMCs reinforced with TiB and TiC particulate. Phase II would develop a viable manufacturing process for ceertain aerospace and commercial components. Commercial applications would involve fabricating tubular shapes - both circular and box tubing - by superplastically forming a final size and shape from a powder metallurgy near-net shape hollow preform. This technology could find use in manufacturing hot gas ducting for aircraft, in automotive exhaust, in stiffened structural tubing, in sporting and recreational goods (golf club heads, lacrosse sticks, and bicycle frames), in corrosion/erosion resistant reaction vessels, and in tubing and fittings for paper making, chemical processing, and seawater service. ***
