Direct observation of the structure of a metallic alloy glass [4]

Under favourable circumstances, high resolution axial bright-field transmission electron micrographs can provide information on the medium-range structure of oxide glasses and amorphous semiconductors¹. Specifically, the presence in an image of localised patterns of fringes, with the fringe spacing related by Bragg's law to the first diffraction peak, provides evidence of correlations in atomic positions over distances in the range 8-15. 'Amorphous lattice fringes' with these characteristics have been studied in many amorphous solids but hitherto have not been reported in glassy metals, although several attempts have been described previously^2-4. We present here what we believe to be the first high resolution axial, bright-field micrographs with lattice resolution of an amorphous metal, taken with the Cambridge University 600 kV high resolution electron microscope (HREM)⁵. The image features obtained indicate that it is now possible to observe directly the microstructure of amorphous metals, thereby emphasising the potential of high resolution microscopy as a tool for furthering the understanding of the structure of amorphous metallic glasses.