Recrystallization, grain growth and phase transformations of cold-worked Zircaloy-2

In the examination of a damaged Zircaloy-2 pressure tube many different alterations of the cold worked starting structure were found. Through heat treatments of original material, temperature/time fields were established and the same characteristic structures obtained as that exhibited in the damaged reactor component. This examination permitted, in combination with microhardness, scanning electron microscopy and microprobe analysis, an estimate to be made of the proportion of overheating experienced by the failed pressure tube. (Auth.)