|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Environmentally Assisted Cracking: Theory and Practice
||The Stress Corrosion Cracking Mechanism of a Cu-free Al-Zn-Mg Alloy in Sodium Chloride Solutions
||Christoph Altenbach, Daniela Zander
|On-Site Speaker (Planned)
Heat treatable Al-Zn-Mg-(Cu) alloys are generally considered susceptible to stress corrosion cracking (SCC), especially when compared to 6000 series. Nevertheless, due to their high strength they own a high potential as a substitution material for steel screws in the automobile industry. Anodic dissolution and hydrogen embrittlement are discussed frequently as possible SCC failure mechanisms, but are not completely understood so far. Particularly in Cu-free systems, SCC was found to be dependent on heat treatment, Zn/Mg-ratio and environment. In the present study the Cu-free alloy AA 7108A in different heat treatments, under-aged, peak-aged and over-aged, was investigated in air and sodium chloride solutions with pH of 6.5 and 3. The influence of external stress was investigated using slow strain rate tests with a strain rate of 5x10-7 s-1. The observed corrosion and fracture mechanisms were correlated to the microstructure using scanning and transmission electron microscopy as well as differential scanning calorimetry.
||Planned: Supplemental Proceedings volume