Leading edge – DUTIFRISK improving bladed disk technology
The DUTIFRISK project has introduced important improvements in bladed disk (BLISK) technologies for aircraft engines, developing and testing a new dual alloy for linear friction welding. The research conducted has paved the way for a new generation of improved disks, which will contribute to the development of safer and more efficient engines in the future.
The ongoing efforts to develop safer and more efficient aircraft engines have led to many innovative changes in engine designs. These innovations often mean greater stresses on the materials and structures used due to higher rotating speeds and exposure to higher temperatures. The recently completed DUTIFRISK (Dual material titanium alloy friction welded BLISK) has developed and validated a new technology for the design and manufacture of BLISKs – key aero engine components, which will help to secure the strong position of Europe's aerospace industry in the world market.
Machined from a single forged piece, BLISKS have already helped to overcome some of the fretting fatigue problems associated with conventional disk-blade attachments. The partners of DUTIFRISK, however, wanted to see if they could improve this technology even further by combining more than one material in the BLISK production process. Their aim was to develop and validate a dual high-strength titanium alloy/dual microstructure linear friction welded BLISK.
“The results of DUTIFRISK have improved our knowledge in a very specialised area relating to the production of BLISKS and the combination of materials than can be used,” notes Dr Olaf Roder of the German company MTU Aero Engines GmbH. “Our aim was to contribute to the development of more efficient and safer aero-engines by exploring the possibilities of combining different materials in a single BLISK so as to find an optimal balance between weight and strength.”
Light and strong
“The performance of an engine is improved by lighter components, while safety is enhanced by ensuring the strength and resistance of the materials used. Less weight leads to lower fuel consumption and, eventually, less pollution,” he explains. “Choosing the right materials on the other hand can improve resistance to stress, fatigue and high temperatures, thus improving safety and lowering maintenance costs.”
The highly innovative BLISK technology resulting from the project allows an optimal material choice for the blades and the disk, leading to a significant increase in cycle performance and reliability and, at the same time, to a notable weight reduction.
The project brought together two European industry leaders in the manufacture and maintenance of aero engines, SNECMA (France) and MTU Aero Engines (Germany). It also included the major Austrian forging company, Bohler GmbH and leading research institutes in France and Spain. The co-operation established was very productive and has led to bi-lateral collaboration that will continue past the end of the project.
Most importantly, the project has succeeded in proving the applicability of the dual alloy BLISK concept to real components. Both industrial project partners, SNECMA and MTU Aero Engines are now in a position to be able to apply the new design (two different Ti Alloys in one component) in the next generation of aero engines. Bohler, for its part, has been able to develop and validate new forging techniques, knowledge and experience it can harness for future work.
“The developments made have been significant,” confirms Roland Schmier, project coordinator. “In addition, to leading to the production of an improved engine component, the project has also helped deepen our understanding of the materials used,” he says. “This will help strengthen the competitive position of the project partners and of the European aerospace industry as a whole.”