Variability in the segregation of bismuth between grain boundaries in copper

The distribution of segregation levels of bismuth to grain boundaries in copper has been measured and compared using Auger electron spectroscopy (AES) and X-ray energy-dispersive spectroscopy (XEDS) in a scanning transmission electron microscope (STEM). The STEM-XEDS measurements showed that there are large numbers of grain boundaries with very low segregation levels which, as they are not embrittled, are not analysed using AES. A crystallographic analysis of a small number of boundaries showed that low segregation levels were not necessarily associated with special, high symmetry boundaries. These results indicate that only a part of the segregation behaviour can be explained by any results obtained using AES and that understanding the relationship between crystallography and brittle behavior will require going beyond a misorientation analysis.