DMREF/Collaborative Research: Accelerated Soft Magnetic Alloy Design and Synthesis Guided by Theory and Simulation

Colorado School Of Mines, Golden CO

Investigators

Abstract

Soft magnetic materials have use in power conversion, conditioning, distribution, and generation technologies, including transportation (electric vehicles), renewable energy (solar inverters), and aerospace (power converters and inductors) sectors. The term "soft magnet" refers to a magnetic material that easily changes magnetic pole directions using small magnetic fields. With over 20 percent of all generated electricity in the US being consumed by industrial electric motor drives, a mere 1 percent improvement in energy efficiency would result in significant financial and environmental benefits. The magnetic components are a major source of energy loss in the above-mentioned applications, motivating the need for soft magnets with better energy efficiency. The design cycle for new soft magnetic materials has so far been informed mainly by direct human engineering intuition and historic knowledge and bias, with materials development occurring by trial-and-error approaches. This Designing Materials to Revolutionize and Engineer our Future (DMREF) award supports research to establish, demonstrate, and validate a computation-guided framework for accelerated discovery of new, better performing soft magnetic materials. This approach will use computational materials science tools to guide alloy design, with the synthesis and experimental validation of properties performed for down-selected new alloys. Recently, new alloys with microstructures comprised of an amorphous matrix and nanocrystalline grains have revolutionized advanced soft magnetic materials by enabling smaller hysteresis than has been achieved in traditional magnetic materials. This award supports research on the design of new alloys of this type using hierarchical, multi-scale, magneto-structural modeling with input from density functional theory calculations of structural and magnetic properties for single-crystals. Micromagnetic theory will provide the constitutive law for the continuum-level model for optimization of realistic microstructures consisting of an amorphous matrix surrounding nanocrystals. The continuum-level modeling represents a fundamental advancement that will provide much-needed insight into the interplay between the microstructure effects and the magnetic properties of the crystalline phase in determining small hysteresis, as well as an operational understanding of the applicability limits of the currently-prevalent random anisotropy model for coercivity. Structural considerations will be evaluated by continuum thermodynamics modeling and resulting magnetic performance characteristics will be evaluated by micromagnetics modeling. Down-selected alloy compositions - as optimized by these computational approaches - will be synthesized using rapid solidification with subsequent annealing and characterized using state-of-the-art structural and magnetic characterization tools.