Description
Orlando Rios1, Hunter B. Henderson1, Min Zou2, Craig Bridges1, Michael Kesler1, Michael Brady1; 1Oak Ridge National Laboratory, 2GE Global Research
A primary limiting factor in the efficiency and flexibility of electric motors and generators is the ability of rotors to withstand mechanical stresses at high rotational velocity. One way to strengthen rotors is to form them from a monolithic material rather than an assembly, but this leads to uncontrolled flux paths and flux leakage associate with support structures. To tune flux paths and maintain a monolithic material, we selectively transform ferrite to austenite through masking and a high temperature nitrogenation treatment in a high-Cr soft magnetic steel. In this study, the kinetics of transformation are explored through magnetization, microstructure, and high-speed differential scanning calorimetry. Additionally, neutron diffraction methods are used to evaluate residual stress that could affect performance in the materials.