Solid state grain alignment of permanent magnets in near-final shape
AssigneeIowa State University Research Foundation, Inc.
InventorsIver E. Anderson, Emma Marie Hamilton White, Matthew J. Kramer, Aaron G. Kassen, Kevin W. Dennis
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Abstract
Magnet microstructure manipulation in the solid state by controlled application of a sufficient stress in a direction during high temperature annealing in a single-phase region of heat-treatable magnet alloys, e.g., alnico-type magnets is followed by magnetic annealing and draw annealing to improve coercivity and saturation magnetization properties. The solid-state process can be termed highly controlled abnormal grain growth (hereafter AGG) and will make aligned sintered anisotropic magnets that meet or exceed the magnetic properties of cast versions of the same alloy types.
Claims14
A method for treating a preshaped magnet body to impart magnetic properties, the step of concurrently heating a preshaped magnet body having a solid state with essentially full density of at least 98% of theoretical and applying a uni-axial stress to the solid state magnet body by applying an external mechanical load thereto such that the uniaxial stress is transmitted through the solid state magnet body in a direction at a temperature where a single phase magnet alloy of the magnet body exists and for a time that results in preferential solid state, stress-biased grain growth that imparts a grain-aligned magnetic microstructure to the magnet body.
Dependencies are inferred from the claim text.