Magnetic Hardening by combination of Equal-Channel Angular Swaging and Rotary SwagingThursday (29.09.2016) 10:15 - 10:30 Part of:
Due to a large growth of electromobility and renewable energy, permanent magnets are gaining more and more importance in the today’s modern technology. Since high performance permanent magnets typically rely on strategic rare earth elements with limited accessibility, there is a growing technological interest in alternative approaches for magnetic hardening aside from alloying. The magnetic properties of a material, such as coercivity and remanence, can be influenced and tailored by the microstructure. One approach to tailor the microstructure is a combination of different types of forming processes which allow a variation of the parameters such as the aspect ratio, grain boundary density and texture.
In the present work, the SPD process Equal-Chancel Angular Swaging (ECAS) and the conventional forming process infeed rotary swaging are applied in order to achieve magnetic hardening of a commercial FeCo alloy. The ECAS process magnetically hardens the material by increasing the grain boundary density by grain refinement while during rotary swaging, a grain elongation as well as a pronounced fiber texture is generated. In the work, it could be shown that it is possible to further process an ECAS rod by rotary swaging. The combination of both forming processes lead to further increase in the magnetic hardness. The change in grain shape, boundary density, and dislocation density as well as the crystallographic texture was examined by EBSD. The microstructural changes could be correlated to the change in magnetic properties measured by VSM. The investigations show the potential of magnetic hardening by superposition of ECAS and rotary swaging.