Suppression of grain boundary embrittlement of Al–5% Mg alloy by immersion in liquid indium

High-temperature embrittlement (HTE) of coarse-grained Al–5% Mg alloy was suppressed by immersion in liquid indium. Characterization using scanning electron microscopy–energy dispersive X-ray spectrometry revealed that this treatment changed the fracture mode from intergranular to transgranular. Indium–sodium binary compounds were also identified at the grain boundaries after fracturing. The suppression of embrittlement was believed to arise from the reduction of accumulated sodium atoms at the grain boundary caused by replacement with indium–sodium compounds.