Radiation damage in stainless steel electron irradiated in a high voltage electron microscope

Damage structure produced in stainless steel by ''in-situ'' irradiation with 1MV electron in a high voltage electron microscope has been observed as a function of irradiation temperature. Small hardly resolvable dislocation loops were produced by the irradiation at 3000C and below. Hexagonal-, diamond- and irregular-shaped loops were observed at 4000C irradiation. During prolonged irradiation the diamond-shaped loops directly developed into dislocation network, while the other faulted hexagonal and irregular shaped loops grew to be dislocation networks after unfaulting. At 5000C irradiation, dislocation loops grew rapidly to be dislocation lines and void nuclei appeared with strain field images. On further irradiation, the void grew larger with little increase in the density. Grain boundary migration toward or away from the highly damaged region was observed at 5000C irradiation. (auth.)