NMR Observation of Melting and Diffusion in
Al/Al-Oxide Nanophase Composites
P. Apte and B. H. Suits
Abstract
High temperature 27Al NMR measurements of Al/Al-Oxide
nanophase composites produced by consolidation of nanoscale
Al particles which have been passivated by exposure to air are
reported. The Al metal is observed to melt at the same
temperature in all the samples independent of grain size and
without a change in the shape of the sample. The results here
confirm previous thermal measurements which show that the Al
metal melts without apparent grain growth in these materials.
On the other hand, the temperature for the onset of rapid
atomic diffusion, as estimated from NMR line widths, shows a
significant sample dependence. Heated samples exhibit a
factor of five increase in hardness and yet remain
electrically conducting.
NanoStructured Materials 10, 917-922 (1998).
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