Effect of precursor phase transition on subsequent martensitic transformation in a Fe-10Cr alloy

Abstract The critical cooling rate of martensitic transformation cooling from 1300 °C is decreased by one order of magnitude, compared to that cooling from 1000 °C in a Fe-10Cr alloy. Analysis indicates that precursor δ→γ phase transition during cooling from 1300 °C significantly decreases the non-chemical driving force of martensitic transformation. The reduction of non-chemical driving force results from the coarsened size of prior austenite grains as well as the decreased frictional energy of interface motion and defect stored energy.