Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


공학

한국표면공학회지 (24권1호 31-41)

Effect of Annealing Temperature on the Nodular Corrosion of Zircaloy-4 Alloy

Zircaloy-4 합금의 Nodule형 부식에 미치는 열처리 온도의 영향

정용환;최종술;임갑순;

연세대학교 공과대학 금속공학과;한국원자력연구소 핵연료재료연구실;

Abstract

The nodular corrosion behavior of Zircaloy-4 alloy was investigated by autoclave test at 50$0^{circ}C$ under 1500 psi for the specimens quenched into water from $700^{circ}C$, 80$0^{circ}C$, 90$0^{circ}C$, and 105$0^{circ}C$. It was observed that the corrosion resistance of Zircalloy-4 specimen increased with increase in annealing temperature, and annealing at $alpha$-region temperatures resulted in nodular corrosion while annealing at the temperature range of $alpha$+$eta$ and $eta$ did not show nodular corrosion. It was also found that the size of nodule formed on the surface of the specimens increased with increase in exposure time in autoclave, but the total number of nodule remained uncha-nged. The corrosion of furnace-cooled specimens progressed mostly in the interior of grains where Fe and Cr alloying elements were largely depleted during the cooling process. However, the grain boundary seemed to act as a barrier to the nodular corrosion. From combining the present results with other works, it is suggested that the nodules nuc-leate in the local region where some of alloying elements are depleted.

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