Researchers at the University of Aalen in Germany have created an advanced characterization method that will allow them to observe microscale structural characteristics and changes during the manufacturing process. Using electron backscatter diffraction (EBSD), scientists hope to develop a clearer understanding of the details of the microstructure of electrical steel, and how manufacturing can lead to magnetic losses. This would prove invaluable information in the field of high-efficiency electric motors, particularly those with tailored speed-torques.
“When you have deformations from machining, it is a great help to make the deformations visible. In order to get deeper insight into the material’s structure, electron backscatter diffraction is really useful. For example, grain size and shape, texture and degree of elastic strains and plastic deformations can be determined.”
Researchers on the project sought to understand how electrical motors could reach higher levels of efficiency. On average, over 5% of electrical energy produced by these motors is lost as heat due to the high rotational speed of traction drives. Scientists believe there must be a way to solve this problem.
Using the advanced characterization method, researchers were able to compare the effects of an assortment of machining types on the microstructure of electrical steel. They were able to see what happened to the structure during machining, and how that impacted the material — and its efficiency — as a whole.
This discovery has provided some valuable insights into magnetic properties. Scientists now believe they can improve ratio between particle size and grain size distribution of the material in question. By controlling the gain growth and recrystallization, scientists could adjust the magnetic properties of the material. This would also allow them to reduce the amount of magnetic losses. Such a discovery could enhance the power and efficiency of electric motors.
The methodology that has resulted from this work will be a vital and exciting new tool for scientists. It will allow researchers to develop a richer understanding of crystalline structures, and how they are disrupted during the machining process. Furthermore, this offers exciting new applications for soft magnetic materials. As a result, the future of electric motors is looking very bright indeed.