Undercooling of superalloys and casting quality of single-crystal turbine blades

以前的高温合金开发集中在高温性能的改善上，而没有考虑单晶部件的可铸造性。在这个提交的研究基金中，将系统地研究当今高温合金的过冷性，以调查它们对铸造缺陷的敏感性。该项目的重点是最新的第四代高温合金。这些将被检查，以找出有关机制有助于实现足够的过冷度，使单晶部件和复杂的几何形状，如涡轮机叶片的制造成为可能。在这里，基本的科学问题，如复杂的多组分合金在有问题的条件下的成核和枝晶生长将在我们的研究的前沿。过冷度对成分的依赖性应通过统计回归、系统的合金添加和相应的显微组织表征来确定。关键合金元素的影响应进行深入研究。本研究的结果将对高温合金的发展做出重要贡献，并将有助于实现所需机械性能与制造单晶部件所需的可铸性的最佳组合。

Previous superalloy development focussed on the improvement of high temperature properties without considering the castability of single-crystal components. In this submitted research grant the undercoolability of today's superalloys will be systematically researched in order to investigate their susceptibility to casting defects. The focus of this project is on the latest 4th generation superalloys. These will be examined in order to find out about mechanisms contributing to the achievement of a sufficient undercooling to make the manufacturing of single-crystal components and complex geometries like turbine blades possible.Here, fundamental scientific questions such as the nucleation and dendrite growth of complex multicomponent alloys under problematic conditions will be at the forefront of our research. The dependency of the undercooling on the composition shall be determined by statistic regression, systematic alloying addition and correspondent microstructure characterisation. The impact of critical alloying elements shall be investigated in depth.The results of this study will form an important contribution to the development of superalloys and will help to achieve an optimal combination of the desired mechanical properties with the required castability for the manufacturing of single-crystal components.