High Temperature Mechanical Properties and Microstructure in 9Cr or 12Cr Oxide Dispersion Strengthened Steels

Oxide Dispersion Strengthened (ODS) ferritic steel, a candidate material for fast reactor fuel cladding, has low thermal expansion, good conductivity, and excellent resistance to irradiation damage high temperature strength. The origin of the high-temperature strength lies in dispersion fine oxides. In this study, creep tests at 700°C or 750°C, which are close operating temperatures reactors, tensile 900°C 1350°C, simulate accident conditions, were conducted on 9Cr ODS steels, M11 MP23, 12Cr F14, confirm growth behavior F14 test samples, there was little oxide decrease number density from initial state, indicating that strengthening by oxides effective during deformation. After deformation development dislocation substructures such as walls subgrain boundaries hardly observed, mobile dislocations homogeneously distributed grains. increased with increasing stress test. ring MP23 both steels decreased higher temperatures. elongation 1100°C, but 1200°C, drastically 1250°C, again 1300°C. temperature. It inferred formation δ-ferrite phase responsible complex change mechanical properties 1200