Observation of an Isothermal Transformation during Quenching and Partitioning Processing

The kinetics of the isothermal transformation, which occurs during a single-step quenching and partitioning (Q and P) process, was analyzed by means of dilatometry. Experiments revealed that an isothermal transformation with very specific characteristics occurred during the hold at the quenching temperature below the martensite start temperature. Although evidence for isothermal martensite transformation has been reported in the past for Fe-C alloys and steel, it is the first time that it is recognized to take place during the Q and P processing of low-carbon ferrous alloys.