Strengthening mechanisms of 2A14 aluminum alloy with cold deformation prior to artificial aging

The introduction of cold deformation prior to aging is an important strengthening method of aluminum alloy. However, it is unclear how many mechanisms of strengthening take effect, and how those mechanisms affect each other during aging process. In this paper, the precipitation kinetics parameters of theta '' phase, theta' phase in aging process after cold deformation were obtained by Differential Scanning Calorimeter ( DSC ) combined with JMA equation. Dislocation densities of the cold deformed specimens were successfully estimated from X-Ray Diffraction (XRD) profile analysis using the modified Williamson-Hall equation. A comprehensive quantitative model for the strengthening of 2A14 aluminum alloy due to precipitation strengthening, solid solution strengthening, grain/subgrain strengthening and dislocation strengthening was presented. The model revealed the evolution law of these four strengthening mechanisms during aging process, and predicted the combined effects and competitive relationship of four strengthening mechanisms on the yield strength of 2A14 aluminum alloys. The accuracy of the model prediction was verified through experiments when the cold deformations were smaller than or equal to 6% and can be used to design aging process of 2A14 aluminum alloy.