UBC Theses and Dissertations
Superplasticity in a dilute zinc aluminum alloy Cook, Richard Charles
The system Zn-0.2 wt. % Al has been investigated to determine under what conditions of strain rate, grain size and temperature the phenomenon of superplasticity may be observed. The analysis and experimental conditions were based on established procedures which have been applied to known superplastic alloys. However the continually decreasing strain rate and grain growth during testing complicate the normal analysis. Based on this study the requirements for superplastic behavior are a fine-grained microstructure, grain boundaries which are relatively free of obstructions and a homolohous temperature of at least 0.42. A model incorporating grain boundary shear and non-continuous grain growth has been proposed to account for the observed superplastic behavior where grain boundary migration is the rate controlling process.
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