Abstract:Effects of magnesium and hydrogen to grain boundary on the fracture energy in 7050high strength aluminium alloy have been calculated using the quasichemical approach. The results indicated that both Mg and H segregation induce the intergranular fracture energy decrease, thus resulting in grain boundary embrittlement, and the embrittlement degree induced by hydrogen is larger than that of magnesium. This conclusion corresponds with the experimental results.

Key words: high strength aluminium alloy; grain boundary segregation; intergranular brittleness