Evolution of helium bubbles induced by stress concentration in He-irradiated aluminium

摘要

By employing an in situ tension experiment in a transmission electron microscope, a stress concentration is demonstrated as a significant contributor to evolution of helium bubbles in a non-uniform stress field. In the stress concentration, a bubble growth occurs through bubble migration and coalescence driven by stress gradients as well as a dislocation slip-induced vacancy absorption upon straining. A bubble-shape evolution occurs after a coalescence of bubbles with similar size. As the bubbles grow to critical sizes, gradual elongation and disappearance of bubbles are found with further straining. (C) 2019 Elsevier B.V. All rights reserved.