Electropulsing-induced strengthening of steel at high temperature

Abstract

Electropulsing usually promotes a metastable phase to evolve towards its equilibrium state. This work reports an alternative case, where electropulsing promotes the decomposition of the stable δ-phase in duplex stainless steel at high temperature. This decomposition enables both the γ-phase and the σ-phase in the steel to survive and hence to strengthen it at high temperature. The hardness of the quenched sample with electropulsing treatment is 49.4% higher than that without electropulsing treatment. A fundamental understanding of the observation is developed.

Keywords:

• electropulsing
• phase stability
• electrical properties
• non-thermal effects
• decomposition
• strengthening
• stainless steels

Acknowledgements

The authors are grateful for financial support towards the project from EPSRC (EP/J011460/1), TATA Steel and the Royal Academy of Engineering.