Effect of Ca on Phase Stability and Oxidation Resistance of Al3Mg2 at Elevated Temperature.

In this study, effect of Ca on phase stability and oxidation of Al3Mg2 at elevated temperature was investigated. From thermogravimetric analysis (TGA) at 420 °C, rapid weight gains in the initial stage and incubation were observed for Al3Mg2 and Ca-added Al3Mg2. After incubation for some time, Al3Mg2 sample exhibited the second weight growth, while Ca added sample exhibited continuous incubation during the testing time. The phase diagrams calculated by Factsage 7.1 revealed that Ca exists as Laves_C36 in Al3Mg2 and also forms Ca3MgAl4O10, following formation of MgO and MgAl2O4-spinel as primary and secondary oxides, respectively, on the surface during oxidation at 420 °C.