Characterization of untransformed ferrite in 10Cr and 12Cr ODS steels

Two new ferrito-martensitic oxide dispersion strengthened (ODS) steels reinforced with (Y, Ti, O) nanoparticles were elaborated using a high-energy attritor. The milled powder was consolidated by hot extrusion at 1050 °C. two types of ODS differ chromium content, 10 wt% Cr and 12 respectively. According to thermodynamic calculations, those grades are supposed exhibit an austenitic transformation high temperatures. X-ray diffraction (XRD) above temperature reveals the presence both ferrite austenite phase. This unexpected phase is assumed be untransformed low ferrite. ??? specific enthalpy monitored differential scanning calorimetry (DSC). fraction calculated dilatometric data confirmed electron backscatter (EBSD) microstructural analysis. quenched samples from domain give image high-temperature partitioning. EBSD maps reveal distinct elementary microstructures, one martensitic inherited other corresponds keeps crystallographic ?-fiber conferred hot-extrusion. has equiaxed areas. In contrast, into distributed as elongated areas, parallel hot-extrusion direction. Moreover, probe micro analyzer (EPMA) mapping exhibits content gradients, consistent partitioning Creep properties evaluated 650 °C for grades. Small-angle X-rays scattering (SAXS) shows similar size distribution particles in