A Critical Review of the Stress Corrosion Cracking (SCC) of Magnesium Alloys

Abstract

This review aims to provide a foundation for the safe and effective use of magnesium (Mg) alloys, including practical guidelines for the service use of Mg alloys in the atmosphere and/or in contact with aqueous solutions. This is to provide support for the rapidly increasing use of Mg in industrial applications, particularly in the automobile industry. These guidelines should be firmly based on a critical analysis of our knowledge of SCC based on (1) service experience, (2) laboratory testing and (3) understanding of the mechanism of SCC, as well as based on an understanding of the Mg corrosion mechanism.

Zn-Mg and Zn-Ag Degradation Mechanism Under Biologically Relevant Conditions

“…The selective dissolution of magnesium in magnesium alloys is associated with stress corrosion cracking (SCC). 8 An evaluation of the sensitivity of zinc-silver alloys to SCC would hence also be of interest when further evaluating this new class of biodegradable alloys.…”

“…7 Hydrogen may also be absorbed by the remaining magnesium implant, which can result in hydrogen embrittlement and premature failure of loadbearing implants. 8 Iron, on the other hand, degrades too slowly for many applications and produces voluminous corrosion products, causing an increase in the volume of the implant. 9,10 Zinc (Zn) was recently suggested as an alternative degradable metal or alloy base.…”

Stress Corrosion Cracking Behavior of Fine-Grained AZ61 Magnesium Alloys Processed by Equal-Channel Angular Pressing

“…All Al-containing magnesium alloys have been confirmed to be susceptible to SCC in distilled water [1]. Generally, the SCC susceptibility of Mg alloys tends to increase with the growing percentage of Al content [11], and a previous study even showed the SCC susceptibility achieved maximize with about 6% Al content [12].…”

“…Magnesium alloys are very attractive light materials, due to a high strength to weight ratio, being pollution-free, non-toxic, and exhibiting easy recovery [1,2], etc. The applications of magnesium alloys in electronics, automobiles, aerospace and the biomedical field are rapidly increasing, but their high chemical reactivity and poor corrosion resistance still severely limit their wider application [3,4].…”

“…Constant efforts have been made to figure out the influencing factors of SCC behavior of magnesium alloys, including alloy composition, the manufacturing process, microstructure and heat treatment [1], etc. Furthermore, it has been demonstrated [5] that hydrogen is crucial to the mechanism of the SCC of magnesium alloys.…”