Work

Optimization of a thixoforming process for Nd-Fe-B permanent magnets by the finite-discrete-element-method

Year: 2025

Type: article

Abstract: Microstructural engineering, especially grain size modification, is an important aspect of improving the magnetic properties of Nd-Fe-B alloys. Previous work of the authors proved that thixoforming in terms of rotary swaging can be an effective and economically feasible method for grain refinement. Brittle Nd2Fe14B grains are fragmented by the rotary swaging process due to mechanical loadings. However, the grain size distribution is non-homogeneous after the forming processes. In order to gain a better understanding of the grain fracture processes, a numerical study based on a Finite-Discrete-Element model with Cohesive Interface Elements is carried out in this work. The approach allows the simulation of crack patterns in brittle Nd2Fe14B grains and thus to observe the crack formation during processing. The resulting fragment sizes are of high interest. Investigations reveal the influence of diameter reduction ratio, impact velocity, impact angles and grain size differences. Qualitative experimental validation confirms the identified conditions that allow for more homogeneous particle size distributions achievable with the new process route.

Source: Journal of Magnetism and Magnetic Materials

DOI: 10.1016/j.jmmm.2025.173188

Authors: Fansun Chi, Enrico Bruder, Karsten Durst, Peter Groche

Institution: Technische Universität Darmstadt

Language: English

Topic: Magnetic Properties of Alloys

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,210

Funder: Deutsche Forschungsgemeinschaft