Abstract
Microcharacterization of creep damage in structural materials of austenitic stainless steel has been performed using a magnetic force microscope in order to understand the degradation mechanism of structural materials in power plants such as advanced fast breeder reactors. Magnetic phases of δ-ferrite are observed in the weld metal of the as-received specimen, and these magnetic phases are interconnected. Magnetic phases of δ-ferrite are also observed in the weld metal of a creep-damaged specimen. However, in this case, the amount of magnetic phases decreases and they are not interconnected. Image processing analyses of the magnetic force microscope images indicate that the degradation of creep damage is related to the area fraction of magnetic phases and the standard deviation of magnetic force microscope images. The degree of degradation can thus be evaluated by microcharacterization using a magnetic force microscope.
