FRG: Microstructure Design of Advanced Multi-Domain Magnetic Materials Under Applied Fields

Ohio State University, The, Columbus OH

Investigators

Abstract

9905725 Wang This Focused Research Group (FRG) integrated program includes experimentation, analysis and simulation to develop a fundamental and technological understanding of the formation of complex multi-domain (e.g., compositional, structural and magnetic) microstructures under applied magnetic and stress fields in magnetic materials. This allows for the possibility of tailoring multi-domain microstructures for desired properties through advanced thermomechanical and thermomagnetic treatments. Material systems investigated include the high-coercive magnetic alloys of Fe-Cr-Co and Co-Pt, whose magnetic domain structure is self-adjusted to the evolving complex multi-phase microstructure. Advanced characterization techniques are used to provide accurate descriptions of the alloy systems upon which realistic analytical and simulation models are formulated. A series of three-dimensional (3D) computer simulations are performed to characterize the size, shape, orientation, spatial arrangement and dynamic switching of the structural and magnetic domains as functions of internal misfit strain and applied magnetic and stress fields. Effects of these microstructural features on the magnetic properties of the alloys are examined. In parallel with the simulations, thermomagnetic and thermoelastic treatments and magnetic property measurements are carried out to validate the simulation predictions and to test key assumptions. Early stages of the program focus on fundamental understanding and model development, while later stages address practical applications of the integrated approach to the design and development of novel multi-domain microstructures for new technological challenges. The grant is co-funded between the MPS Office of Multidisciplinary Activities and the Metals Research Program in the Division of Materials Research. %%% This FRG should have important impact on science, technology and education. Improved understanding of the complex microstructures in these systems under applied fields is expected. The numerical methods developed will allow realistic 3D computational prototyping of the multi-domain microstructures for a range of advanced applications. These advances will minimize the need for trail-and-error experiments in microstructural engineering for new alloy development. The computational design tools with user-friendly interfaces to be developed are uniquely suited for adoption to undergraduate and graduate instructions. The project will also provide a unique opportunity for the students involved to be exposed to a combination of advanced simulation methods and experimental characterization techniques. It will provide an excellent vehicle for knowledge transfer to a new generation of materials scientists and engineers who are able to contribute directly to science based microstructural engineering in their workplace. ***