The Mechanism Behind the Oxidation Protection of High Mg Al Alloys with Beryllium
Journal article, Peer reviewed
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Original versionMetallurgical and materials transactions. B, process metallurgy and materials processing science. 2018, 49 (5), 2846-2857. 10.1007/s11663-018-1340-6
The addition of beryllium to Al-Mg alloys is known to cause a dramatic decrease in oxidation; however, the mechanism behind this protective effect is not yet fully understood. To aid in finding an alternative to the toxic Be, a fundamental study of Be additions has been carried out. Industrial samples containing 2 ppm Be and a model alloy with 100 ppm Be were oxidized at temperatures between 550 °C and 750 °C in a horizontal tube furnace. The oxide layer and oxide–metal interface were investigated using SEM, FIB, and XPS. It was found that Be forms a uniform oxide layer at the oxide–metal interface which slows the diffusion of Mg and Al from the metal into the oxide layer resulting in a reduced oxidation rate and an increase in the time for breakaway oxidation to occur.