Rare earth permanent magnets are the most powerful and thus most useful magnet for energy conversion devices (motors and generators). However, Nd and other important rare earth elements suffer from supply chain issues, motivating us to use the materials more efficiently. Additive manufacturing (AM) produces near-net-shape and net-shape parts, significantly altering design paradigms and reducing waste during manufacturing. Our lab is using laser powder bed fusion (LPBF) to build Nd-Fe-B-based permanent magnets.
Jeff Shield,
University of Nebraska-Lincoln
However, current Nd-Fe-B-based alloys are not designed for the solidification conditions encountered during LPBF. We are developing new alloy compositions amenable to the solidification conditions during LPBF, and determining AM processing conditions that result in fully dense parts free of defects. For alloy development, we use melt spinning as a LPBF proxy because it has similar solidification conditions, including highly directional heat flow and similar solidification rates. Its high-throughput capabilities allow many alloy compositions to be readily investigated, and the solidification conditions can be easily altered by adjusting the wheel speed. LPBF processing schemes that result in fully dense, crack-free parts have been established for these brittle alloys with complex solidification paths.
Prof. Jeff Shield is the Robert W. Brightfelt Professor of Engineering in the Department of Mechanical & Materials Engineering at the University of Nebraska-Lincoln. Prof. Shield received his B.S. in Metallurgical Engineering from the South Dakota School of Mines and Technology and Ph.D. from Iowa State University. Research interests are in the general area of microstructural development in materials during processing, formation of nanostructured materials, and development of nanoscale structures for functional devices.