Combined influence of Be and Ca on improving the high-temperature oxidation resistance of the magnesium alloy Mg-9Al-1Zn. (1st July 2017)

• Record Type: Journal Article
• Authors: Tan, Qiyang; Mo, Ning; Jiang, Bin; Pan, Fusheng; Atrens, Andrej; Zhang, Ming-Xing
• Is Part Of: Corrosion science. Volume 122(2017)
• Page Start: 1
• Page End: 11
• Publication Date: 2017-07-01
• Subjects: A. Magnesium -- A. Alloy -- B. SEM -- C. Oxidation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2017.03.023
• Languages: English
• ISSNs: 0010-938X

Abstract

Graphical abstract: Highlights: The oxidation resistance of Mg-9Al-1Zn was improved by combined alloying with Be and Ca. Alloying with 20 wt ppm Be plus 0.5 wt.% Ca let to higher oxidization resistance than alloying with 60 wt ppm Be. Combined alloying led to a more oxidation resistant alloy containing less toxic Be. The synergistic effect and mechanism of Be and Ca in improving the oxidation resistance of Mg alloys was discussed. Abstract: The present work showed that the oxidation resistance of Mg-9Al-1Zn at elevated temperatures was improved by combined alloying with Be and Ca. AZ91 alloyed with 20 ppm (wt) Be and 0.5 wt.% Ca had higher oxidization resistance than that of AZ91 containing 60 ppm (wt) Be. The improved oxidation resistance was attributed to (a) the formation of a Be-reinforced compact CaO-MgO composite layer on the alloy surface, and (b) suppressing the grain boundary evaporation of Mg by (i) the elimination of Mg-Al eutectic micro-constituent, and (ii) the increase in thermal stability of the β-Mg17 Al12 due to the Ca alloying.