Engineering steels at the nanoscale for improved performance

The increasing demand for improved performance in steel has led to a number of developments that largely focus on microstructure control through advanced alloy design and thermomechanical processing. At the same time, there has been a marked increase in our capacity to characterize the microstructure over a wide range of scale lengths. This paper focuses on the control of microstructure at the ultrafine to nanoscale and the associated characterization. Specific examples will include a study of strain-induced precipitation for control of the austenite; interphase precipitation for high-strength, ultrafine and nanoscale microstructures through transformation control, and the use of solute atoms for strengthening. The advanced characterization methods employed include high-resolution transmission electron microscopy, atom probe tomography and small-angle neutron scattering. The areas of application for these steels are largely focused on the automotive sector, although there is potential for this knowledge to be applied to other structural steels.