Light weight materials gain outstanding interest for automotive as well as aviation applications, since fuel savings are only realized by reducing the overall weight of the vehicles. The so called intermetallic alloy Gamma-titanium aluminide is counted among one of the most promising light weight materials.Gamma titanium aluminide alloys have been studied extensively in recent years.
However due to the high strength, the high hardness and brittleness at room temperature Gamma-TiAlalloys are regarded as difficult-to-cut materials.
A major effort has been made over the last 20 years to introduce TiAl-based alloys into the aerospace marketplace as engineering components.
The biggest problems which are holding back the manufacturing of engineering components from TiAl-based alloys is their processing. For this reason, this project aims at the development of an economical approach to the production of complex TiAl parts through the optimization of the very difficult machining process.
The main objective of the project was the improvement of tools for the machining of heat resistant aeronautic materials.
The project followed the sequent steps:
- A first field test was done for choosing suitable parameters for working Gamma-TiAlalloys: both tool life and economical implications of the cutting process were evaluated and finally dry cutting and proper cutting parameters were founded.
- A basic study on the geometry of uncoated end mills was done, thus improving the cutting performances and adopting a first step of geometric optimization of the tools.
- A basic study on different coating performances was done and it was decided to adopt a nano-gradient structure, while nano-layer structure did not perform well.
- A further step of development was done adopting Nanogradient coatings on the optimized end mills geometry, the results were good: AlSiTiN proved to be the best coating.
- A final improvement was done adopting a fine polishing on the coating surface, it is a ultra-finishing of the final end mills, again the performances were improved.
The results of this project will lead to a decrease in the manufacturing cost of Gamma-TiAlalloys, which will increase competitiveness of the aeronautical industry.
It is to notice that the machinability of this materials was not a sure statement, but this project shows that it is possible, with really promising results. It is anyway to investigate the influence of the production technology used for obtaining Gamma-TiAlalloys that could give really different results regarding machinability: it is aim of the project to deeply investigate this aspect and this will be done together with Bildu Lan and Escuela de Ingenieros de Bilbao. In fact the Nanotoolga project is not ended and the end of the project is scheduled for June 2012.
