Influence of cumulative strain on microstructure and mechanical properties of multi-directional forged 2A14 aluminum alloy

2A14 aluminum alloy was subjected to multidirectional forging (MDF) with a constant strain rate at 350 °C, to different cumulative strain. The effects of cumulative strain on microstructure and mechanical properties of 2A14 aluminum alloy were investigated. The inhomogeneity of deformation during MDF was improved and grains of the alloy were gradually refined by increasing cumulative strain, while dislocation density first increased and then decreased with increasing cumulative strain in the range 0.4-7.2. After subsequent T6 aging, fine and equiaxed recrystallization grains with large-angle grain boundaries were more easily formed at relatively higher cumulative strain, and the optimized mechanical properties were achieved when cumulative strain was up to 3.6, with ultimate tensile strength of 505 MPa, yield strength of 435 MPa, Vickers hardness of 178 Hv and elongation of 16.8% at room temperature. The improvement in mechanical properties of the alloy was attributed to the presence of fine recrystallized grains which are uniformly distributed and high dislocation density, as well as precipitation strengthening.