On the growth of annealing of stacking-fault tetrahedra in gold

Abstract

The growth and annealing of stacking-fault tetrahedra in quenched gold were studied by transmission electron microscopy using an interrupted anneal of matched bulk specimens. Specimens quenched from 930°C were initially aged to completely nucleate the tetrahedra. Subsequent measurements of the vacancy precipitate ensemble as a function of annealing time at 40°C showed continuous growth of the stacking-fault tetrahedron distribution, while the tetrahedron density remained constant. The directly measured variation of precipitated vacancy concentration with time agreed reasonably well with that obtained under similar conditions from resistivity annealing studies. It is concluded that stacking-fault tetrahedra exhibit continuous growth by the successive absorption of vacancies. Observations of the annealing of the final tetrahedron ensemble at temperatures up to 600°C showed shrinkage of the tetrahedra with no tendency for tetrahedron collapse. The results are discussed in terms of previous work.