鋯合金碘應力腐蝕

Iodine Stress Corrosion Cracking of Zircaloy

本研究探討鋯 -4合金於碘蒸汽環境下之應力腐蝕行為。以慢速固定拉伸速率試驗（CERT）於各種碘蒸汽濃度環境分別在200，250，300和350 ℃溫度進行應力腐蝕實驗，並以延伸率變化作為應力腐蝕敏感指標（SCC Susceptibility Index）。結果顯示在200與250 ℃時有發生應力腐蝕現象，此時應力腐蝕敏感指標亦產生和緩變化；但在300及350℃時，雖然敏感指標發生急遽變化，卻是發生腐蝕反應為主，且拉伸速率愈慢時，腐蝕導致的應變量減少更加明顯。

The iodine-induced stress corrosion cracking of Zircaloy-4 was investigated under various iodine pressure at temperatures of 200, 250, 300, and 350℃ by a constant extension rate test (CERT). SCC susceptibility index was evaluated according to the change of elongation. The results showed that the SCC phenomenon occurred at temperatures of 200 and 250℃ while SCC susceptibility index revealed mild reduction; However, the corrosion was dominant at 300 and 350℃ and caused the obvious change of the SCC susceptibility index. The slower extension rate also enhanced the corrosion effect.