Fundamental analyses regarding the influence of aluminum content in titanium alloys on the electric discharge machinability and the resulting component functionality

钛合金具有很高的比强度和耐温性，在提高涡轮机械部件的效率方面具有巨大的潜力。该领域的材料发展趋势集中在高度合金化的金属间γ钛铝化物上。因此，借助传统工艺加工钛合金部件变得越来越具有挑战性。然而，电火花加工（EDM）是独立于材料的机械性能，因此EDM工艺是一个重要的替代加工这些难以加工的钛合金。涡轮机部件上的特定几何元素现在已经默认通过EDM工艺制造，例如原型构造领域中涡轮机叶片上的密封槽和冷却孔或扩压器的内轮廓和整体叶盘上的叶片几何形状。可以假设，在不久的将来，对EDM工艺的需求将增长，但是这需要工艺变得更有效，并且需要确定性工艺配置的可能性。现有技术表明，到目前为止，还没有足够的关于钛合金的知识来实现这种确定性配置。此外，还没有澄清低合金钛（如Ti-6Al-4V）的哪些规格导致了这样的事实，即与其他材料（尤其是高合金钛铝化物）的加工不同，电火花加工工艺需要反向电极性。本研究主要针对钛、铝合金在电火花加工过程中不同相含量和分布（微观结构）对加工性能的影响进行了基础研究。这将最终产生一个基于模型的过程和材料的理解，将允许确定性的沉没EDM工艺配置钛和钛合金。最重要的是，第三和第四个研究年将通过静态和动态弯曲测试，研究与EDM工艺相关的组件功能方面。这将允许最终用户根据最终组件功能方面设计其制造过程。

Titanium alloys inherit great potential when it comes to increasing efficiency in turbo machinery components due to their great specific strengths and temperature resistances. The trend in material developments in this field focuses on the highly alloyed intermetallic gamma titanium aluminides. Thus, the machining of components out of titanium alloys with the help of conventional processes is getting increasingly challenging. Nevertheless electric discharge machining (EDM) is independent from the materials mechanical properties, so EDM processes represent an important alternative for the machining of these hard-to-machine titanium alloys. Specific geometric elements on turbomachinery components are already nowadays manufactured by EDM processes by default, e.g. seal slots and cooling holes on turbine blades or inner contours of diffusors and blade geometries on blisks in the field of prototype construction.For the near future it can be assumed that the demand for EDM processes will grow on, but this needs the process to become more efficient and the possibility for a deterministic process configuration. The state of the art shows that there is not enough knowledge about titanium alloys up to this day to realize this deterministic configuration. Furthermore it has not been clarified which specifications in low alloyed titanium like Ti-6Al-4V are responsible for the fact, that the Sinking EDM process - unlike the machining of other materials, especially the highly alloyed titanium aluminides - need an inversed electric polarity. The exact break point as a function of alloying contends is not known.This proposal addresses the fundamental research on the influence of different phase fractions and distributions (micro structure) of the main alloying elements titanium and aluminum on the process performance during Sinking-EDM. This will finally generate a model based process and material understanding that will allow the deterministic Sinking EDM process configuration for titanium and titanium alloys. On top of that, the third and fourth research year shall address research on component functionality aspects in relation to the EDM process by static and dynamic bending tests. This will allow end users to design their manufacturing process based on resulting component functionality aspects.