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

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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.