We perform room temperature and elevated temperature He implantation of bulk Cu-Nb nanocomposites synthesized by accumulated roll bonding (ARB). Transmission electron microscopy (TEM) reveals that nanoscale He precipitates form preferentially along Cu-Nb interfaces during implantation at 20 °C and 450°C. Bubble-free zones may be identified near interfaces after implantation at 450°C. He implantation at 480°C results in large, faceted cavities in thick Cu layers and highly elongated cavities in thin Cu layers. Only nanoscale bubbles are seen in Nb layers after implantation at 480°C. Similar to vapor deposited Cu-Nb multilayers, ARB Cu-Nb nanocomposites exhibit He precipitate morphologies that are highly sensitive to implantation temperature and layer thickness.
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This work was supported by the Center for Materials in Irradiation and Mechanical Extremes (CMIME), an Energy Frontier Research Center (EFRC) funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award No. 2008LANL1026 . WZH was partially supported by the new faculty start-up funding from XJTU , China. WZH also acknowledges I.J. Beyerlein for fruitful discussion as well as E.G. Fu and J. Zhang for their assistance with the He implantation.