Effect of T616 and its modified processes on mechanical properties of novel high strength A1-Li alloy-2A97

Based on a novel high strength Al-Cu-Li-X alloy-2A97, the effect of T616 and its modified processes on the properties investigated by SEM and tensile test. The results show that when the alloy is heat treated by triple ageing, with secondary low temperature ageing at 80 ℃ after initial ageing at 155 and 150℃, and final re-ageing at 135 and 165 ℃, the tensile properties are close to the peak level of aged alloy in T6 temper. The addition of plastic deformation after and prior to secondary ageing favor the T1（Al2CuLi） and δ（Al3Li） precipitation during final re-ageing at 135 and 165 ℃ corresponding to triple ageing, so the Al-Li alloy displays higher strength for the modified processes of T616. The microstructures consist of δ, T1 and θ＂/θ＂ （A12Cu） phase for single and triple aged alloy, the number density and volume fraction of δ phase increase for T616 and its modified processes correspond to single ageing.