Microstructure and defect controlled additive manufacturing of gamma titanium aluminides for function-based control of local materials properties

更好的目标是了解工艺参数、凝固和冷却条件与组织形成之间的基本关系，并系统地研究其对添加制备的伽马钛铝化物变形和断裂行为的影响。通过使用EDX和EBSD探测器、X射线计算机层析、高温X射线衍射仪和仪表化硬度图进行光学和扫描电子显微镜的综合组织分析，将对工艺参数和组织形成之间的关系有一个基本的了解。与过去的研究相比，在IfWW上，通过使用不同的能源(激光和电子束)以及工艺内和后处理(感应、热等静压、时效、固溶退火)可以产生不同的组织结构。为此，将研究基本参数(扫描速度、沉积速率、衬底温度)以及不同建筑方向(垂直、水平)的影响。同时，由于WPT基于机制的测试方法的进一步发展，将能够对疲劳变形和断裂行为进行基本分析，并将微观结构特征与疲劳性能相关联，从而有效地表征伽马钛铝化物在室温和高温下的疲劳行为。特别是，为了实现组织和性能之间的基本关系的基于模型的描述，结果在相关矩阵中的连续传输将使研究结果能够转化为工业中添加制造的伽马钛铝化物。科学主题和目标：Christoph Leyens，IfWW(第一个申请者)·研究不同的工艺参数，如气氛(真空、惰性气体)对合金元素的汽化行为的影响。·由于后续热处理而产生不同的微结构形成。·开发工艺、组织和性能之间的关联矩阵，用于制造其微结构针对局部性能进行优化的结构。Frank Walther，WPT(第二个申请者)·表征微结构和缺陷形成作为工艺参数和后处理的函数，以及它们对准静态和疲劳变形和断裂行为的影响。·进一步发展基于机理的测试方法，以仪表化的载荷增加和恒幅测试为基础，对室温和高温下的疲劳行为进行资源高效的表征。·开发基于物理的模型，用于描述微结构和缺陷特征对室温和高温下的疲劳行为的影响。

The superior target is to understand the fundamental relationships between process parameters, solidification and cooling conditions and the microstructure formation and to systematically investigate its impact on the deformation and fracture behavior in additively manufactured gamma-titanium aluminides. Due to a comprehensive microstructure analysis with light and scanning electron microscopy by using EDX and EBSD detectors, X-ray computer tomography, high temperature XRD and instrumented hardness mappings, a fundamental understanding of the relationships between process parameters and microstructure formation will be reached. In contrast to past studies, different microstructure formations can be generated by usage of different energy sources (laser and electron beam) as well as in- and post-process heat treatments (induction, HIP, aging, solution annealing) at IfWW. For this purpose, the basic parameters (scanning speed, deposition rate, substrate temperature) as well as the influence of different building directions (vertical, horizontal) will be investigated. Simultaneously, a fundamental analysis of the fatigue deformation and fracture behavior and a correlation of the microstructure characteristics with the fatigue properties will be allowed due to a further development of the mechanism-based testing methodology of WPT for a resource-efficient characterization of the fatigue behavior of gamma-titanium aluminides at room and high temperatures. Especially, the continuously transfer of the results in correlation matrices in order to realize a model-based description of the fundamental relationships between microstructure and properties will enable a transformation of the research results to additively manufactured gamma-titanium aluminides in industry.Scientific topics and goals:Christoph Leyens, IfWW (1st applicant) • Investigation of influence of different process parameters, e.g. atmosphere (vacuum, inert gas) on the vaporization behavior of the alloying elements.• Generation of different microstructure formations due to a follow up heat treatment.• Development of correlation matrices between processing, microstructure and properties for manufacturing of structures whose microstructure is optimized for the local amount of properties.Frank Walther, WPT (2nd applicant) • Characterization of microstructure and defect formation as a function of process parameters and the post processing as well as their impact on the quasistatic and fatigue deformation and fracture behavior.• Further development of the mechanism-based testing methodology on basis of instrumented load increase and constant amplitude tests for a resource-efficient characterization of the fatigue behavior at room and high temperatures.• Development of a physically-based model for description of the impact of microstructure and defect characteristics on the fatigue behavior at room and high temperatures.