The effect of Be addition on precipitation behavior and mechanical properties in Al-Cu-Li-Mg-(Ag)-Zr alloys

摘要

The effect of Be addition on mechanical properties and precipitation behaviors was studied by hardness and strength measurement and TEM analysis in Al-Gu-Li-Mg-(Ag)-Zr alloy. Be additions result in acceleration of ageing response, increasing elongation without reduction of yield strength. Be free A alloy shows G. P. zone which was produced in Al-Cu alloy system in early stage of ageing. #theta# ~1 phase and T_1 phase coexisted in peak and over-ageing stage. Be added B and C alloy have already formed T_1 and #theta# ~1 phase in under-ageing stage, and were decreased the density of #theta# ~1 phase in peak and over-ageing stage compared with that of Be free A alloy, but T_1 phase was distributed finely and homogeneously. New precipitates having square shape were found, which have not been reported yet in this alloy system.