EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

The increasing demand for lightweight and energetically sustainable automobile materials has brought the application of the Quenching and Partitioning (Q&P) process into consideration for the development of martensitic stainless steels with improved combinations of strength and ductility. The resulting microstructures are formed by a matrix of carbon depleted martensite and films of retained austenite. This work investigates the thermal stability of retained austenite after applying Q&P processing in two martensitic stainless steels differing in carbon content. The thermal stability is investigated in-situ by magnetic measurements upon cooling down to -100⁰C. Results showed complete stabilisation of retained austenite up to -60⁰C in both alloys and further improvement upon cooling down to -100⁰C in the alloy with the lowest carbon content. The dependence of these observations with the morphology, fraction and carbon content of retained austenite present at room temperature is discussed.