Effects of cold rolling and heat treatment on microstructure and mechanical properties of 15Cr-15Ni ODS austenitic steel

Oxide dispersion strengthened (ODS) austenitic steels are considered as the promising candidate cladding materials application for advanced nuclear energy systems. However, the microstructure of ODS austenitic steels fabricated by mechanical alloying is usually not very homogeneous. Thermal mechanical treatment is an effective method for controlling microstructure of alloys. In this work, the effect of cold deformation and subsequent heat treatments on the improvement of microstructure homogeneous and mechanical property of a 15Cr-15Ni ODS austenitic steel was systemically investigated by means of electron backscatter diffraction, transmission electron microscopy and tensile test. Results show that the average grain size decreased and the distribution of grains was more homogeneous after optimized thermal mechanical treatment. The deformation of cold rolling and heat treatment temperatures shows obvious influence on the average size of dispersion particle, the proportion of high angle grain boundary, Schmidt factor and tensile property of 15Cr-15Ni ODS austenitic steel.