11/2018

The art of green 21st-century forging

Example of a forged TiAl blade © Leistritz
Example of a forged TiAl blade © Leistritz
The aviation industry wants to become greener. To achieve this, research institutes and industry are working together on the development and industrialization of lightweight materials that reduce the weight of aircraft. This also increases energy efficiency and reduces CO2 emissions. In the engine sector, new titanium-aluminide materials make an important contribution in this regard. The Remscheid-based company Leistritz Turbinentechnik GmbH has actively supported the development of this new class of materials and, among other things, developed a forging process that enables the successful reshaping of these extremely brittle, intermetallic materials.

The place for titanium aluminides in modern engines is the low-pressure turbine. Where traditionally only nickel materials that can withstand the highest temperatures could be used, titanium-aluminide turbine blades weighing only half as much are now being used – and are proving their worth.

Isothermal forging – the solution for stubborn problems
The way to the first perfect forged blade – that is, a blade free of cracks and cavities – was not easy. The material is extremely brittle and cannot be formed using conventional forging methods. The key to success was the development of an isothermal forging process, a process with extremely precise temperature control that is adapted to the poor formability of the intermetallic material. The blanks are slowly and continuously shaped into their final form on a hydraulic press at a constant high temperature.

Green aviation made in Germany
Leistritz Turbinentechnik GmbH is the first and only company in the world to date that can forge titanium aluminide. This unique selling point once again demonstrates the global pioneering role of the German aerospace industry. In recent years, a new production line for this new class of products has been installed at the Remscheid plant and series production has been ramped up. The forged turbine blades are used in engines for the Airbus A320neo.

Titanium aluminides open up new horizons for the aviation industry. They allow engines to save even more resources and be more fuel efficient and cleaner, because any weight reduction will reduce fuel consumption and CO2 emissions. The new material thus makes an important contribution to achieving the aviation industry's ambitious climate-protection targets.