Quenching defects in aluminium plus 10 at. % zinc

Thin foils of aluminium plus 10 at. % zinc were prepared from quenched samples and their microstructure was studied by transmission electron microscopy. The quenched microstructure was found to vary with the amount of ‘high-temperature oxidation’ that had taken place. The influence of high-temperature oxidation has been thought to be due to the atomic hydrogen which is probably introduced into the alloy lattice when water vapour reacts with the aluminium at high temperature. The microstructure of samples not subjected to such attack was dominated by numerous, large, circular, helical dislocations and prismatic dislocation loops. The solute clustering process was observed to be influenced by, if not dependent upon, a super-saturation of vacancies.