The Composition-Dependent Oxidation Film Formation In Mg-Li-Al Alloys

The composition-dependent oxidation film formation behaviour in Mg-Li-Al alloys was investigated via diffusion couple experiments. The concentration gradients of alloying elements across the bonded interface resulted in both microstructural and oxidation behaviour changes. The interdiffusion of alloying elements led to four different matrix zones. Different oxidation behaviours in single-phase zones were caused mainly by Li concentration variations among them, specifically, higher Li contents bring about thicker oxide films. A thicker oxidation film induced by accelerated oxidation in the duplex diffusion zone was observed compared to those in the single-phase zones, which was a result of galvanic degradation.