Quantification and Modelling of the Multiphase-Coupled Strengthening Effect in Al-Cu-Li Alloy

Abstract

After aging heat treatment, Al-Cu-Li alloy, in general, contains a variety of precipitated phases that jointly influence the age-strengthening effect on the alloy. In this work, a multiphase-coupled strengthening model has been established on the basis of a dislocation bypassing mechanism. The model considered situations with different proportions of two strengthening phases, T1 and θ′, and then obtained the dimension and volume fractions of these two strengthening phases via experiments. The values predicted by the multiphase-coupled strengthening model and the classical strengthening superposition model were compared with the measured results. The multiphase-coupled strengthening model established in this work had better consistency with the measured results. Moreover, the modeling method proposed in the paper can also be extended to the system having over two primary strengthening phases. Hence, the model can contribute towards the development of a multi-component precipitation strengthening process for aluminum alloys.

Keywords

• Al-Cu-Li alloy
• multiphase-coupled strengthening
• precipitated phase
• transmission electron microscope