New Nd2Fe14B-based High Performance Permanent Magnets with Improved Toughness

A major problem that exists with Nd2Fe14B rare earth permanent magnets is brittleness, or poor toughness, that leads to low manufacturing yields, high component rejection rates, and limits the ability of the material to be shaped appropriately for specificapplications. The objective of this effort is to demonstrate the feasibility of significantly improving the toughness of sintered R2Fe14B-based magnets and obtain new sintered R2Fe14B-based magnets that can be subjected to grinding, machining, anddrilling. The magnets will maintain their high magnetic properties. The approach is primarily to improve the plasticity of the Nd-rich grain boundary phase by modifying its composition and refining the microstructure of the R2Fe14B-based magnets. Toaccomplish this, we will prepare sintered rare earth permanent magnets of the general form (Nd(1-x)REx)2(Fe(1-y)TMy)14B using standard powder metallurgy approaches. Rare earth substitutions for Nd include Dy and Pr, while transition metal substitutionsfor Fe include Cu, Ni, Ti, Nb, Co, and V. Standard powder metallurgy techniques will be employed to make sintered magnets based on the Nd2Fe14B phase. The approach to improving the toughness of the conventional sintered Nd2Fe14B-based permanent magnetsis to further improve the plasticity of the Nd-rich grain boundary phase, and refine the microstructure of the magnets.The payoff for DoD and commercial systems includes improved high performance rare earth permanent magnets with higher processing yieldsthat will significantly reduce the cost and increase the availability of complex shaped R2Fe14B magnets.