Microstructural anisotropy of ferritic ODS alloys after different production routes

Abstract

Concepts for future generation fusion reactors have demanding requirements for the structural materials. High neutron doses and elevated temperatures form a harsh environment in which present commercially available materials cannot be used. A new class of oxide dispersion strengthened (ODS-) materials which are currently being developed have a high chance of meeting these requirements.The application of ODS steels as functional or structural application strongly depends on the availability of large batches of materials. Since no commercial ODS-alloys are available at the moment, investigations on large scale batches are crucial for future applications.The effects of powder particle size distribution on the microstructural properties were studied by scanning electron microscopy with electron backscatter diffraction. Although a homogeneous and fine grain size distribution was achieved after rolling, areas with different amounts of deformation were found. Microstructural properties and anisotropy effects are correlated to Charpy-impact tests. The materials after rolling shows a DBBT well below −50°C with excellent impact energies. Detailed investigations on the crystallographic textures concluded the work.