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

该项目旨在通过化学和微观结构的改性，大幅度改善基于钛-钽和钴-镍-镓的高温形状记忆合金的性能。在该项目的第一阶段，确定了具有较高相变温度的富钛成分。这些成分是开发具有更好的功能稳定性和更好的(热)机械性能的新合金的基础。为此，将应用组合材料科学(薄膜)的方法以及生产和表征块状材料的过程。薄膜材料库包括大范围连续的三元和四元合金系统，将用磁控溅射方法制备，并将使用足够的高通量方法进行表征，目的是有效地识别具有特殊性质、相和结构的成分。然后将制造HIT-组合物，并以散装形式进行表征。该项目旨在更好地了解高温形状记忆合金相形成的热力学和动力学方面。它将被调查，在什么条件下出现哪些相，以及这如何影响形状记忆性能。对于钛-钽和钴-镍-镓基合金，该项目都将研究如何修改这些材料的微观结构，以改善其功能性能。因此，将发展对元素微结构过程的理解。最后，将进行形状设定的研究，并将开发薄膜和块体演示器并进行表征。

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.