MICROSTRUCTURE AND MECHANICAL BEHAVIOUR OF Al-Li-Zr AND Al-Li-Cu-Mg-Zr ALLOYS

The aging response,tensile and impact properties of two kinds of Al-Li based alloys have been studied.The microstructure,deformation as well as fracture behaviour in the alloys were observed with SEM and TEM.It was found that the mechanisms of deformation and fracture for different heat-treated alloys with the same chemical composition are quite different.The causes leading to the drop of ductility,toughness as well as anisotropy in peak-aged alloys have been analysed.Finally,possible methods to improve the ductility and toughness of the al- loys have been discussed.