PLASTICITY OF OXIDE DISPERSION-STRENGTHENED FERRITIC ALLOYS

Two 13%Cr oxide dispersion strengthened (ODS) ferritic alloys, DT and DY, exhibiting different oxide particle size distribution and a chi ph ase precipitation were studied. Their tensile properties have been tes ted from 20 to 700 degrees C. Experimental observations during room te mperature tensile tests performed in a scanning electronic microscope have shown that the main damage mechanism consists in microcraking of the chi phase precipitates on grain boundaries. These alloys are high tensile and creep resistant between 500 and 700 degrees C. Their stron gly stress-sensitive creep behaviour can be described by usual creep l aws and incorporating a threshold stress below which the creep rate is negligible.