Liquid metal embrittlement of aluminium by segregation of trace element gallium

The effect of small amounts of gallium on liquid metal embrittlement of model binary AlGa alloys containing 50–1000 ppm2 Ga is studied. Ga segregation did not occur by annealing in the temperature range 300–600 °C because of the high solid solution solubility of Ga in aluminium. Alkaline etching caused significant enrichment of Ga at the surface by dealloying. Diffusion of Ga from the surface into the grain boundaries caused liquid metal embrittlement of samples containing at least 250 ppm Ga. Segregated Ga dissolved back into aluminium by annealing for 1 h at 600 °C after etching, eliminating the grain boundary embrittlement.