Influence of Temperature and Strain Rate during Thermomechanical Treatment of a Metastable Austenitic TRIP Steel Compacted by SPS/FAST

High‐alloy Fe–19Cr–3Mn–4Ni–0.5Si–0.17N–0.17C TRIP/TWIP steel samples are processed by SPS/FAST (Spark Plasma Sintering/Field‐Assisted Sintering Technology) and subsequently thermo‐mechanically treated by Quenching‐Deformation‐Partitioning (QDP). Because a martensite start temperature (M_s) does not exist for this material, it is not possible to form as‐quenched α’‐martensite during the QDP treatment. Therefore, α’‐martensite is formed by strain‐induced transformation. To investigate the influence of the compressive deformation step of the QDP treatment (referred to as pre‐deformation) and the combined α’‐martensite formation on the microstructure and the mechanical properties, the deformation temperature is varied between −60 °C and 20 °C for two different strain rates (0.0004 s⁻¹ and 1 s⁻¹). The results show that a reduction in pre‐deformation temperature and a low strain rate increase the volume fraction of strain‐induced α’‐martensite during pre‐deformation. Furthermore, the compressive yield strength increases. It is obvious that the austenitic‐martensitic QDP‐treated steel could be assigned to the 3^rd generation of Advanced High Strength Steels (AHSS). The steel exhibits compressive offset yield strengths of between 1400 MPa and 1700 MPa as a function of the QDP conditions and the α’‐martensite content which is formed during pre‐deformation.