The importance of permanent magnets in the future economy as well as their expected increase in demand are well-established. Due to the status as critical raw materials of the rare earth elements, there is a strong motivation to replace rare earth permanent magnets in various applications, where intermediate performance is required, with rare earth free magnets. The τ-phase of the MnAl-system is a very strong candidate for this task.

Recently, hot-extrusion of milled MnAl C-Ni powders has equalled the state of the art for this material, which was set by the former industrial production in Japan [1]. All precursors of the hot extrusion utilized thus far were isotropic. An <001> fibre texture is imparted to the material during extrusion but significant improvements in the magnetic properties would be expected by increasing the texture quality. The current work investigates the implementation of a novel, highly textured ε-phase precursor powder [2] into the hot extrusion process in an attempt to further refine the texture quality. This aims to improve upon the current state of the art, approaching the upper limits derived from the intrinsic properties of the τ-phase. The development of this novel processing route is assisted by cutting edge characterization techniques that provide new insights into the development of different microstructures and their impact on the magnetic properties.

[1] L. Feng et al., Acta Materialia 199 (2020) 155–168.

[2] F. Jürries et al., J. Phys. D: Appl. Phys. 56 (2023) 415004.