Effect of Be Addition on the Precipitation Behaviors and Mechanical Properties in Al-Cu-Li-Mg-Zr-(Ag) Alloys

The effect of beryllium (Be) on the precipitation behaviors and mechanical properties of Al–Cu–Li–Mg–Zr–(Ag) alloys was investigated. The results show that adding 0.02%Be to Al–Cu–Li–Mg–Zr–(Ag) alloys, the elongation of the alloy increased without significant decrease in strength and the aging response was accelerated. In a Al–Cu–Li–Mg–Zr–(Ag) alloy, G.P. zone was formed at early aging time (2 h) and T1 and q′ phases were formed at peak-aging and over-aging times, while in Al–Cu–Li–Mg–Zr–(Ag)–Be alloys T1 and q′ phases were formed at early aging time (2 h) and the density of q′ phase was very low and fine T1 phases were homogeneously distributed at peak-aging and over-aging times.