TEM Study of the Influence of Microstructure on the Superplastic Behavior of a U-5.8 Wt % Nb Alloy

摘要

The anomalous superplastic behavior of the U-5.8 wt % Nb alloy in the gamma sub 1 single-phase field is characterized utilizing dilatometric and transmission electron microscopy (TEM) microstructural analyses. It has been suggested that sluggish Nb diffusion kinetics account for this anomalous behavior. A simple diffusion model was considered to determine whether total dissolution of gamma sub 2 could occur within two hours at 670 sup 0 C. This ''thick film'' diffusion analysis suggests that remnants of the prior alpha + gamma sub 2 microstructure can still be present in the gamma sub 1 phase field for up to two hours at 670 deg C. 4 refs., 9 figs. (ERA citation 11:004766)