Dependence of the Growth Rate of Interstitial Loops on Irradiated Crystallographic Directions in Electron Irradiated Pure Aluminum

Abstract

Pure aluminum was irradiated at 120°C with 200 keV electrons in an electron microscope to examine the dependence of the growth rate of interstitial loop (I-loop) on the direction of incident electrons. I-loops grew proportionally with the irradiation time at 120°C. When the specimens were irradiated so that the I-loops were visible by diffraction contrasts, the growth rate depended on both directions of the incident electrons and the diffraction conditions, while it did not depend on the diffraction condition when all the I-loops were invisible. The dependence of the growth rate of I-loops on the diffraction condition may be due to the change of effective electron flux along the atomic rows by dynamic diffraction. The displacement cross section is determined by the growth rate of I-loops when all I-loops are invisible. The threshold energy profile of the fundamental triangle in pure aluminum was obtained with a combination of the steepest descent and the conjugate gradient technique.