High resolution electron microscopy study of the (Sigma)11 (113)/(110) symmetric tilt grain boundary in pure Al and Al-1.5 wt% Cu

摘要

Identical bicrystals of pure Al and Al-1.5 wt.% Cu were prepared by diffusion bonding in ultra-high vacuum. The boundary chosen was the (Sigma)11 (113)/(1(bar 1)0) symmetric tilt grain boundary. Characterization of the atomic structure of and segregation to the boundary was performed by high resolution transmission electron microscopy along the common (110). The stable sites for Cu segregation were probed using electronic structure calculations. Boundary atomic structures were simulated using embedded atom potentials. The Cu was found to segregate to this boundary by occupying sites removed from the mirror plane boundary by one (113) plane. This prediction was compared to experimental micrographs through high resolution image simulation. The experimental results are consistent with the predictions of the theoretical calculations.