Reverse α-α ? phase separation in Fe-20Cr-6Al alloy

摘要

The reverse α-α′ phase separation in Fe-20Cr-6Al alloys has been monitored by differential scanning calorimetry in as-hot rolled and recrystallized samples previously aged at 435 °C. The splitting in the position of the minima, and the increasing enthalpy change involved, might be explained in terms of dissolution of α′ particles with different compositions and volume fractions. These results are fully consistent with the α-α′ phase separation kinetics determined by atom probe tomography during ageing at 435°C. The monitoring of activation energy for α′ dissolution indicates that it is faster in as-hot rolled samples. Finally, the activation energy evolution indicates that there is first a dissolution of β′ Fe(AlTi) phase followed by α′ dissolution.