At first glance, glass might not seem like the ideal candidate for crafting robust electromechanical components. Yet, researchers at Saarland University in Germany are overturning this notion with their innovative use of glass-like metals, significantly boosting the performance of electric motors.
Electric motors, whether in small gadgets like toothbrushes or large vehicles like electric cars, rely on the interaction between a spinning rotor and a stationary stator. This interaction generates a dynamic magnetic field, necessitating constant realignment of microscopic magnetic regions within the metal. Traditional materials, with their ordered crystalline structures, resist this realignment, resulting in energy losses – a problem known as iron losses.
Prof. Ralf Busch, leading the research initiative, states, “We are looking into ways of cutting these efficiency losses by improving the materials used in electric motors. In today’s motors, the stator and rotor components are made from conventional soft magnetic, coarse-grained iron alloys. Although these alloys are already optimized, they still exhibit relatively high hysteresis losses during re-magnetization. We want to replace these conventional crystalline alloys with amorphous, glass-like alloys, as they lose hardly any energy during re-magnetization.”
Metallic glasses, unlike traditional metals, lack a crystal lattice. Their atoms are arranged randomly, akin to glass, allowing magnetic domains to reorient without interference during magnetic field changes. This free reorientation minimizes energy loss during magnetization cycles, thereby enhancing motor efficiency and reducing heat production.
Busch further elaborates, “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. The magnetic properties of metallic glasses are therefore exceptionally well suited for use in electric motors.”
Pasquale D’Angiolillo/UdS
The term “metallic glass” may seem misleading, as it evokes images of fragility. However, these materials often surpass steel in strength. The designation “glass” pertains solely to the amorphous atomic arrangement. This unique structure is achieved by melting a blend of elements and rapidly cooling the molten form to prevent atom organization into a crystal lattice.
In the development of motor components, the team employed Laser Powder Bed Fusion, a sophisticated metal 3D printing method. This technique involves melting fine metal powder layer by layer with a laser, then cooling it swiftly to maintain its glass-like, amorphous state. This method is vital for preserving the advantageous magnetic properties of the material.
The primary objective of Busch’s EU-supported research was to find a metallic glass alloy that not only replaces traditional motor materials but is also suitable for 3D printing. This goal has now been realized.
“We selected hundreds of alloys and tested their resistance to crystallization. In an alloy containing five elements, that meant searching through a five-dimensional compositional space. If an alloy fails, it’s back to the drawing board for a complete redesign. The breakthrough came just over a year ago,” says Ralf Busch.
Three alloys have been identified by Busch and his team that resist crystallization and possess the necessary properties for successful 3D printing of glass-like metallic motor components. The widespread application of electric motors could see significant benefits from this advancement. Enhanced efficiency and longevity in motors could lead to faster, more energy-efficient electric vehicles, drones with greater endurance, e-bikes with extended ranges, and industrial machinery that consumes less power while performing better.
This innovative project is part of the larger AM2SoftMag (Additive Manufacturing of Amorphous Metals for Soft Magnetics) initiative, receiving over €3.5 million (US$4.035 million) in EU funding.
Source: Saarland University
Original Story at newatlas.com