Persistence Of Crystal Orientations Across Sub-Micron-Scale "Super-Grains" In Self-Organized Cu-W Nanocomposites

We use precession electron diffraction to investigate the crystallographic character of copper (Cu)-tungsten (W) nanocomposites fabricated via physical vapor co-deposition at 400 degrees C. We observe sub-micron-scale regions, where apparently disconnected Cu and W grains have near-identical crystallographic orientations. This persistence of grain orientations suggests Cu and W grains within these regions are interconnected in 3-D when they first form and may be considered as intercalated, sub-micron-scale "super-grains". Indeed, atom probe tomography provides direct evidence of 3-D interconnectivity of W domains. Our findings shed light on the structure and self-organization mechanisms of nanocomposites formed by spontaneous phase separation of co-deposited metals. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.