Effect of the aging process and pre-deformation on the precipitated phase and mechanical properties of 2195 Al-Li alloy

Third-generation Al-Li alloys, represented by 2195 Al-Li alloy, have considerable application opportunities in lightweight aerospace structures. This work investigates the effect of the aging temperature, single/double aging strategies and pre-deformation on the precipitation behaviors of 2195 Al-Li alloy. The influence and correlation between the precipitated phase and mechanical properties, especially the tensile strength, ductility and failure fracture mode, were further studied. The results indicate that increasing the aging temperature can significantly improve the aging kinetics, thereby precipitating the large size T1 phase and decreasing the number density accordingly. Double aging is beneficial to the uniform size and distribution of the precipitated phase, which reduces the unevenness of micro-deformation. The pre-deformation increases the number of nucleation sites of the T1 phase, thereby significantly reducing the average size and increasing the number density. Pre-deformation can directly increase the strain hardening by generating dislocations while indirectly increasing the precipitation strengthening by refining the size and increasing the number density of the T1 phase. The mechanical properties and fracture mode of materials are related to the dislocation density and the type, size, distribution and number density of the precipitated phase.