Research at the Oak Ridge National Laboratory is validating the premise that UHMF processing of ferromagnetic materials can significantly alter phase transformation kinetics and microstructural evolution. This presentation will discuss results and ramifications from some experiments performed using a 33T maximum field strength magnet. For these experiments, a Fe-15Ni binary plus SAE 1045, 52100 and a high strength bainitic steel were exposed to various thermal histories both with and without a magnetic field. Temperature measurements, metallography and hardness measurements indicate a significant shift in phase transformation kinetics and resulting microstructure. Temperature data shows that the transformation temperature during continuous cooling is increased by approximately 80°C in the presence of a 30T magnetic field. An approximation of ƒ¢Gg®a associated with the applied magnetic field is estimated for a 1045 steel. These results are supplemented by the resulting microstructures that reveal a significant modification in product phase volume fractions. The application of a magnetic field during continuous cooling of a high strength bainitic steel has produced a new microstructure not possible without the additional thermodynamic driving force associated with a 30T magnetic field.

This research was funded through the Department of Energy Industrial Materials of the Future Program and the Oak Ridge National Laboratory Laboratory Directed Research and Development Program.