Metadislocation core structure and atomic model for metadislocation motion

摘要

We have analyzed the atomic structure of a metadislocation core using aberration-corrected high-resolution electron microscopy. It is shown that the metadislocation core is highly ordered and based on atomic clusters. It possesses a multiscale structure with an inner core comprising the full strain of the metadislocation, and an outer core which is not strained but has a cluster structure modified with respect to the bulk. We have developed the first atomic model for metadislocation motion based on repetitive jump patterns along various crys-tallographic directions. It involves the movement of about 100 atomic positions per step of metadislocation motion. Characteristic parallel "paired jumps" of neighboring atomic columns lead to a net flux of atoms towards the metadislocation core which is consistent with the negative climb mode of metadislocation motion.