Observation of anisotropic damage production in electron-irradiated molybdenum

Anisotropic damage productions were examined in electron-irradiated molybdenum by using high voltage electron microscope. Formation of defect clusters was most enhanced for electron beams with the exact zone axis directions and decreased with an increase in a deviation angle from the axes. Saturated densities of defect clusters produced by the irradiation were used as a measure of damage production, since linear relationship was found between electron flux and the saturated density of defect clusters. From the comparison between the electron flux dependence and orientation dependence of defect cluster formation it was concluded that the enhancement of damage production is due to the locally increased electron flux at the atomic positions effective for atomic displacement. (author)