Effect of large pre-deformation on microstructure and mechanical properties of 7B52 laminated aluminum alloy

With the continuous upgrade of weapons, improving the mechanical properties of 7xxx laminated aluminum alloys for tank armor is a very important task. In this study, the 7B52 laminated aluminum alloy was strengthened through the successive solution treatment, large pre-deformation of 50%, and aging process. The yield strength, ultimate tensile strength, and interlaminar shear bonding strength of this alloy remarkably increased to 558 MPa, 593 MPa, and 93.8 MPa, respectively, which exceeded the values obtained after the traditional solution and aging processes. The effect of the large pre-deformation on the microstructural evolution and mechanical behavior of the 7B52 alloy was examined as well. The mechanical properties depended on the presence of dislocations, low-angle grain boundaries, and tiny precipitates in the alloy structure. The introduction of numerous dislocations and low-angle grain boundaries via large pre-deformation were beneficial for the full precipitation of tiny precipitates during the aging process. According to theoretical calculations, precipitation and dislocation strengthening were the dominant strengthening mechanisms. Moreover, because of its finer grain size, higher dislocation density, and larger number density of precipitates, the 7A62 alloy exhibited higher strength increments than those of the 7A52 alloy after pre-deformation. Therefore, a large predeformation may serve as an effective method for improving the mechanical properties of 7xxx laminated aluminum alloys for their application in the military industry.