EU project advances AM metallic glass for electric motors
As part of the AM2SoftMag (Additive Manufacturing of Amorphous Metals for Soft Magnetics) project, researchers from Saarland University, Saarbrücken, Germany, are developing metallic glass alloys for the Additive Manufacturing of electric motors. The research, supported by €3.5 million in EU funding, is being conducted by a team led by Professor Ralf Busch alongside Professor Matthias Nienhaus and international partners.
E-motor inefficiencies
Electric motors are widely used in applications ranging from e-bikes and drones to electric toothbrushes. While they convert electrical energy into motion, inefficiencies remain, particularly at higher speeds and smaller scales. These inefficiencies are largely attributed to ‘iron losses’, which arise during the repeated magnetisation and demagnetisation of motor components.
Within a motor, a rotor rotates inside a stationary stator, generating a changing magnetic field. This requires continuous reorientation of magnetic domains within the material, leading to internal friction and heat generation. In conventional crystalline alloys, this process is hindered by the material’s microstructure, resulting in energy loss.
Busch’s team is exploring the use of amorphous, glass-like alloys to address these losses. Unlike conventional soft magnetic iron alloys, these materials exhibit significantly lower hysteresis losses due to the absence of a crystalline structure. Energy losses are further reduced in nanocrystalline materials with extremely small grain sizes, or in fully amorphous materials.
Metallic glass alloys
The metallic glass alloys developed by the research team are said to enable smoother magnetisation reversal, helping to reduce heat generation and improve motor efficiency. According to Busch, this approach could lower energy consumption across a wide range of electric motors and extend the operating range of devices such as drones and e-scooters. He also notes that these alloys avoid the use of critical elements such as cobalt.
The alloys under development contain 70-80% iron and are processed using Additive Manufacturing. Busch has worked extensively in this field, collaborating with organisations including NASA and the German Aerospace Center. His team has also conducted experiments on metallic glasses in microgravity aboard the International Space Station and holds multiple patents for advanced alloy systems.
Metallic glass’ strength reportedly exceeds that of many steels, while its amorphous structure (e.g. lacking long-range atomic order) enables improved magnetic performance. “Because metallic glasses have no crystallites, the magnetic regions – known as Weiss domains – are not obstructed and can reorient freely when the magnetic field changes,” explained Busch. “The magnetic properties of metallic glasses are therefore exceptionally well suited for use in electric motors.”
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The team is using Laser Powder Bed Fusion (PBF-LB) Additive Manufacturing to produce motor components from these alloys, building parts layer by layer with thicknesses of approximately 50 µm. Careful control of cooling rates is required to prevent crystallisation and retain the amorphous structure, consistent with Additive Manufacturing principles.
Developing suitable alloys proved challenging, as candidates must vitrify, exhibit appropriate magnetic properties, and be compatible with Additive Manufacturing. The team evaluated hundreds of compositions, effectively exploring a five-dimensional compositional space. Three alloys have now been identified that resist crystallisation and can be processed into fully amorphous components.
Current efforts are focused on scaling the process for industrial application and optimising PBF-LB parameters.
The AM2SoftMag project consortium includes Professor Isabella Gallino (TU Berlin), Heraeus AMLOY Technologies (Germany), IMDEA Materials Institute (Spain), Istituto Nazionale di Ricerca Metrologica (INRIM, Italy), and AMAZEMET (Poland). Heraeus AMLOY is responsible for the Additive Manufacturing of the magnetic components, while partners contribute expertise in materials processing, characterisation, and powder production.
