Study of Hot Salt Stress Corrosion Crack Initiation of Alloy IMI 834 by using DC Potential Drop Method

摘要

DC potential drop technique was employed during the slow strain rate tests to study the hot salt stress corrosion crack (HSSCC) initiation at 300 and 400℃. Threshold stresses for HSSCC initiation were found to about 88% of the yield strength at both temperatures, but the time from crack initiation to final failure (Δt_(scc)) decreased significantly with temperature, which reflects larger tendency for brittle fracture and secondary cracking. The brittle fracture features consisted of transgranular cracking through the primary α grain and discontinuous faceted cracking through the transformed β grains.