PSI - Issue 79

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ScienceDirect

Procedia Structural Integrity 79 (2026) 313–321

28th International Conference on Fracture and Structural Integrity - 3rd Mediterranean Conference on Fracture and Structural Integrity

Fatigue behavior of composite NdFeB specimens Daniel Hofferberth a,* , Felix-Christian Reissner a , Jörg Baumgartner a Fraunhofer-Institute for Structural Durability and System Reliability, LBF, Bartningstr. 47, D-64289 Darmstadt

Abstract This paper reports on the results of the investigation of compound materials, made of a thermoplastic matrix and magnetic NdFeB particles under cyclic loading at Ambient Temperature. The influence of the aging parameters on the fatigue behavior of the specimens as well as the influence of mean stresses were investigated to evaluate the materials’ durability and reliability. A standard assessment approach, based on the Highly Stressed Volume V 90% , commonly used for sintered steels was applied and adapted to verify its applicability for these novel material types. The findings provide insights into the potential of thermoplastic-neodymium composites for applications requiring enhanced fatigue resistance and structural integrity.

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of IGF28 - MedFract3 organizers Keywords: Fatigue, bonded magnets, Highly stressed Volume, Mean stress sensitivity

1. Introduction

Rare-earth permanent magnets, particularly NdFeB, are indispensable for electrification, wind energy, and high-performance drive systems. However, rare-earth element prices are rising, and countries without domestic deposits face heightened supply and price volatility. Establishing efficient magnet-recycling streams can reduce import dependence, recover critical elements (e.g., Nd, Dy), and improve supply security. Conventional recycling routes, such as pyrometallurgy, hydrometallurgy, and electrochemical recovery, can reclaim rare earths from mixed scrap but are energy ‑ intensive, costly, and generate process effluents that require careful treatment [Kaya2024]. Emerging direct routes such as hydrogen decrepitation and HDDR (hydrogenation– disproportionation–desorption–recombination) enable magnet ‑ to ‑ magnet recycling by retaining alloy chemistry and

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of IGF28 - MedFract3 organizers 10.1016/j.prostr.2025.12.339