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

钛合金具有很大的比强度和耐温性，在提高涡轮机械部件的效率方面具有巨大的潜力。这一领域的材料发展趋势集中在高合金化的金属间化合物伽马钛铝化物上。因此，用传统工艺加工钛合金零件的难度越来越大。然而，电火花加工与材料的力学性能无关，因此电火花加工是加工这些难加工钛合金的一种重要选择。在样机制造领域，叶轮机械部件上的特定几何元件目前已经默认由电火花加工工艺制造，例如涡轮叶片上的密封槽和冷却孔或扩散器的内轮廓和叶盘上的叶片几何形状。在不久的将来，可以假设对电火花加工工艺的需求将会增长，但这需要工艺变得更有效率和确定性工艺配置的可能性。目前的技术水平表明，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的构型。此外，还不清楚像Ti-6Al-4V这样的低合金钛的哪些规格是造成这一事实的原因，即沉没电火花加工-不同于其他材料的加工，特别是高合金化的钛铝化物-需要反转的电极性。关于电火花加工中主要合金元素钛和铝的不同相组成和分布(显微组织)对加工性能的影响进行了基础研究。这最终将产生一个基于模型的工艺和材料理解，将允许钛和钛合金的确定性沉没电火花加工工艺配置。最重要的是，第三和第四个研究年将通过静态和动态弯曲试验研究与电火花加工过程相关的部件功能方面。这将允许最终用户基于所产生的组件功能方面来设计他们的制造工艺。

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.