Optimum properties of quenching and partitioning steels achieved by balancing fraction and stability of retained austenite

It is found that the optimum mechanical properties of Q&P steels are not necessarily obtained when the volume fraction of retained austenite is maximum, but they can be achieved by an optimum balance between the fraction and stability of retained austenite. The present work proposes a new microstructurally-based method to design a proper quenching temperature to obtain an optimum microstructure comprising fine martensite laths and alternatively-distributed thin austenite films, which has the optimum balance between fraction and stability of retained austenite, leading to the optimum mechanical properties of Q&P steels. (C) 2018 Acta Materialia Inc Published by Elsevier Ltd. All rights reserved.