Functionally graded Co-Ni-Ga high-temperature shape memory alloys manufactured via ultrasound assisted 3D laser-based directed energy deposition

通过超声辅助 3D 激光定向能量沉积制造的功能梯度 Co-Ni-Ga 高温形状记忆合金

• 批准号: 507664574
• 负责人: Professor Dr.-Ing. Stefan Böhm
• 金额: --
• 依托单位: Fachgebiet für Trennende und Fügende Fertigungsverfahren
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/507664574?language=en
• 关键词: Functionally; graded; Co; Ni; Ga

High-temperature shape-memory alloys (HT-SMAs) are characterized by transformation temperatures above 100 °C. Envisaged applications are cost- and resource-efficient actuators and sensors in a high temperature regime. One of the most promising HT-SMAs is Co-Ni-Ga, which is characterized by comparatively low costs, excellent functional properties up to temperatures of about 500°C and a low dependency of transformation stresses on temperature. However, Co-Ni-Ga possess a difficult workability and shows a strong dependency of functional properties with respect to grain size and texture. Within the scope of the applied project, 3D laser-based direct energy deposition (DED) should be used to overcome previous limitations of workability and to tailor microstructural and, thus, functionally graded structures. By locally superimposed ultrasonic waves, it will be feasible to create different microstructures not only over several layers but also within a single layer, thus paving the way for three-dimensionally graded structures. The ductility of the alloy as well as the transformation temperatures will be improved by post processing heat treatments. In particular, lower transformation temperatures will be realized by introducing precipitates into the matrix and higher transformation temperatures will be realized by changing the shortrange order. A comprehensive microstructural and functional characterization, in particular by means of in situ methods, will enable elementary insights in the relation between processing, microstructure and functional properties.

高温形状 - 内存合金（HT-SMAS）的特征是高于100°C以上的转换温度。但是，在温度下，温度约为500°C，而依赖性应力则具有差异性的可加工性。用于克服工作能力和量身定制的微观结构的限制，从而通过局部叠加的超声波进行了功能分级的结构，可以可行 - 逐渐分配的结构。 。