In situ superplasticity experiments in the 1 million volt electron microscope

Abstract

SUMMARY In situ tensile straining was carried out in the 1 million volt electron microscope in an attempt to clarify the mechanism(s) of superplasticity in the Zn/Al eutectoid alloy. The dynamic microstructural observations in the 1 MV microscope at 100°C at an m value of ∼0.3 were consistent with 100 kV observations of specimens thinned from the bulk and showed that under the experimental conditions used, the predominant mechanism is diffusion of the zinc‐rich (β) phase. It has been theoretically predicted by Lifshitz that diffusional creep and grain‐boundary sliding are inseparable. This is verified by these in situ observations.