STRESS CORROSION CRACK GROWTH RATE TESTING OF NOVEL COMPOSITE ARREST SPECIMENS

摘要

Stress corrosion crack (SCC) arrest tests have been conducted on composite material specimens to study the SCC susceptibility of highly SCC resistant materials. The "composite arrest" test method entails fabricating composite material specimens consisting of a highly SCC susceptible material welded to a highly SCC resistant material. Results from Alloy 690, Alloy 690 weld metal and stainless steel composite arrest specimen tests showed that these materials are extremely resistant to SCC in deaerated water environments. Under aggressive 360°C (680°F) test conditions, cracks readily grew within the SCC susceptible starter material but did not transition into growth within the SCC resistant materials. In contrast, SCC readily grew within Alloy 600 control specimens. Results from extensive specimen analytical (microprobe, AEM, FIB, EBSD) characterization efforts and SCC mechanistic insight will also be discussed.