High-performance alloys for additive manufacturing of energy converters

Currently, only a handful of commercial alloys are available for the additive manufacturing of electric motor components. In order to make electrical machines even more efficient in the future, new materials are needed that are specially tailored to their requirements.

With those requirements in mind and under the direction of Prof. Dr. Dagmar Goll, the Institute for Materials Research (IMFAA) at Aalen University is using a new “rePowder” ultrasonic atomisation system from Amazemet. The system, which was financed as part of a large-scale equipment project, forms the basis for the development of customised high-performance alloys – for example for energy converters, energy storage systems and carbide metals. “The plant provides an excellent basis for genuine material innovation: we are now able to develop completely new materials of very high quality out of pure elements or master alloys – especially in small quantities for developing alloys for highly specialised applications,” reports Prof. Dr. Dagmar Goll.
She says that the procedure combines precision with efficiency: metallic material is melted by plasma or induction and then guided onto an ultrasound-operated sonotrode. The vibrations atomise the liquid metal into droplets, which solidify into a spherical powder when they cool down. Depending on the ultrasonic frequency, particle sizes of 30 to 100 micrometres are possible – ideal for 3D printing. “The spherical shape is crucial for even flow and precise processing,” explains Felix Trauter, a doctoral student at IMFAA. “We can use it to produce alloys with precisely defined properties that are not available anywhere else.”
The induction or plasma melting capability allows virtually any material to be processed. With a maximum temperature of around 3000°C, almost any material can be worked with, from aluminium to highly reactive special alloys and tungsten. Even exotic materials such as moon dust are possible. “For our research into energy storage systems, electric motors and generators, we need materials with very specific magnetic or mechanical properties. Previously, we had to work with the next best materials available – now we can develop them ourselves,” says Dr. Thomas Kresse, researcher at IMFAA.
The system also facilitates direct recycling according to the cradle-to-cradle principle: material can be directly converted back into high-quality raw material for additive manufacturing at the end of its useful life. “Support structures from the printing process are turned back into usable powder – without any loss of quality,” explains doctoral student Trauter. The material is recycled for the specialised use for which it was originally manufactured. This enables fast iteration cycles in material development while efficiently leveraging the available resources.
Source: Aalen University