(BRI) Direct and Inverse Design Optimization of Magnetic Alloys with Minimized Use of Rare Earth Elements
Technical Report,01 Sep 2012,30 Oct 2015
Florida International University Miami United States
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This project deals with the industry-wide need for developing a new generation of high strength magnetic materials with minimal use of rare earth elements. We studied an extended AlNiCo family of magnetic alloys with 8alloying elements and no rare earths. Existing theoretical formulations and accompanying software can predict only certain physical properties of such materials and they are currently limited to at most three alloying elements. We used advanced semi-stochastic algorithms for constrained multi-objective optimization in combination with experimental testing and verification of candidate alloys. These optimization algorithms allow for concentrations of a large number of alloying elements to be optimized so that several physical properties of the alloy are simultaneously extremized in a Pareto sense. This approach was successful in evolving chemical concentrations of an initial set of candidate alloys with negligible magnetic properties into concentrations of alloys with properties comparable to commercially available AlNiCo alloys. Pattern recognition statistical algorithms were also used to elucidate relationships among different alloying elements and each of the desired magnetic properties of the alloys. Sensitivity analysis of the variation of concentrations of each of the alloying elements revealed that some of the alloying elements have practically negligible influence on the magnetic properties of the AlNiCo type alloys. Research is recommended on determining which of the alloying elements could be replaced with small amounts of rare earth elements and optimizing thermal treatment protocols for higher magnetic performance of such alloys.