High-resolution electron microscopy characterization of nanocrystalline grain boundaries in gold–copper alloys

The grain boundary structures of gold–copper nanocrystalline specimens are investigated using transmission electron microscopy to reveal how fundamental changes in the atomic arrangements present at grain boundaries may affect the attainment of ideal strength. In addition to high-resolution lattice imaging, the inverse fast-Fourier transform image-processing technique clearly shows the crystalline nature of the grain boundary and the presence of the extended defects. Selected area diffraction patterns are used to determine the orientation between grains. Differences are detailed so as to distinguish how nanocrystalline alloys behave wherein free volume attributed at grain boundaries is deemed responsible for localized deformation and changes in strength behavior.