|About this Abstract
||Materials Science & Technology 2020
||Environmentally Assisted Cracking: Theory and Practice
||Microstructure and Beta Phase Distribution Effects on Environmental Fracture Susceptibility in Al-Mg Alloys
||Matthew McMahon, William Golumbfskie
|On-Site Speaker (Planned)
Al-Mg alloys are popular structural materials in marine applications due to their high strength-to-weight ratio and general corrosion resistance. However, extended time in service has demonstrated that these alloys may become sensitized through precipitation of β phase on the grain boundaries, which enables intergranular corrosion and/or stress corrosion cracking (IG-SCC). New alloy tempers such as – H128 are promising for slowing this intergranular precipitation, but questions remain concerning the IG-SCC susceptibility of this heat treatment once a significant sensitization level has been reached (Nitric Acid Mass Loss Test (NAMLT) value greater than 15 mg/cm2).
The present research compares the IG-SCC susceptibility of AA5083-H128 to other common AA5xxx-series alloys at constant sensitization level. Slight differences in IG-SCC susceptibility are evident due to microstructural differences, such as percent recrystallization, as well as differences in yield strength. These differences are resolved based on understanding of hydrogen concentration in the fracture process zone.