Study on microstructure and properties of a novel high strength aluminum lithium alloy 2A97

The microstructural evolution and mechanical properties of the novel high strength Al-Li-Cu-X alloy-2A97 during aging at 135℃ for different time after water quenching and 4% plastic deformation was studied by hardness test,tensile test,TEM and XRD.The results show that the microstructure consist of T_1(Al_2CuLi),θ′/θ″(Al_2Cu),δ′(Al_3Li) precipitates and δ′/β′(Al_3Zr) coupled precipitates for 2A97 alloy aged at 135℃ after water quenching and plastic deformation.With increasing aging time,the amount and size of T_1 precipitates increase,and the amount of δ′ precipitates increases,but its size decreases.Tensile strength increases to a peak value and then decreases,and tensile elongation decreases with increase of aging time for the 2A97 alloy.At the meantime, hardness of the alloy increases with increasing aging thime.The ultimate tensile strength,yield tensile strength,and elongation are 577MPa,519MPa,and 6.7%,respectively,for the alloy aged at 135℃ for 48h.