High temperature soft magnetic materials: FeCo alloys and composites

We have systematically investigated the microstructural effects including g rain size, precipitation, and structural order parameter on the high temper ature magnetic and mechanical properties of FeCo-based commercial alloys. A t high temperatures the equilibrium nonmagnetic precipitates significantly deteriorate the soft magnetic properties. Poor mechanical properties are ma inly due to the nature of the ordered structure of FeCo alloys. Based on th is understanding we have designed new magnetic composites by reinforcing Fe Co alloys with high strength fibers. The magnetic and mechanical properties can thus be improved independently through optimizing the magnetic matrix and fiber network, respectively. These new magnetic composites show excelle nt soft magnetic and mechanical properties. In particularly, negligible cre ep has been observed at 600 degreesC.