Options
2011
Book Article
Titel
Stress corrosion cracking (SCC) of magnesium (Mg) alloys
Abstract
This chapter reviews current research into stress corrosion cracking (SCC) in magnesium (Mg) alloys, particularly intergranular stress corrosion cracking (IGSCC) and transgranular stress corrosion cracking (TGSCC).A nearly continuous second phase along grain boundaries causes IGSCC. The second phase accelerates corrosion of the adjacent matrix by micro-galvanic corrosion; the applied stress opens the crack and allows propagation through the alloy. IGSCC can be avoided by appropriate Mg alloy design. TGSCC is the intrinsic form of SCC. This is caused by an interaction of hydrogen (H) with the microstructure, so a study of H-trap interactions is needed to understand this damage mechanism, and in order to design alloys more resistant to TGSCC. This understanding is urgently needed if Mg alloys are to be used safely in service because prior research indicates that many Mg alloys have a threshold stress for SCC of the order of half the yield stress in common environments, in cluding high-purity water.