Combinatoric alloy development, casting and thermomechanical Optimization of high-temperature shape memory alloys

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The project aims at substantially improving the properties of high-temperature shape memory alloys based on Ti-Ta and Co-Ni-Ga by chemical and microstructural modifications. In the first phase of the project Ti-rich compositions with high transformation temperatures were identified. These composi-tions are the basis for developing new alloys with better functional stability and better (thermo-) me-chanical properties. For this, methods of combinatorial materials science (thin films) together with processes for the production and characterization of bulk materials will be applied. Thin film materials libraries, containing large continuous ranges of ternary and quaternary alloy systems, will be fabricat-ed by magnetron sputtering and will be characterized using adequate high-throughput methods with the aim of efficiently identifying compositions with special properties, phases and structures. Hit-compositions will be then fabricated and characterized in bulk form. The project aims at a better un-derstanding of thermodynamic and kinetic aspects of phase formation in high temperature shape memory alloys. It will be investigated, which phases appear under which conditions, and how this affects shape memory properties. Both, for Ti-Ta- and Co-Ni-Ga-based alloys the project will investigate how microstructures of these materials can be modified for improving the functional properties. Therefore, an understanding of elemental microstructural processes will be developed. Finally, research on shape setting will be performed as well as thin film and bulk demonstrators will be developed and characterized.