Anisotropy in creep-ageing behavior of textured Al-Cu-Mg alloy

Abstract

Creep age forming (CAF) has been developed to manufacture large complex components in aerospace industry. However, crystalline textures in initial material for CAF process may influence the creep ageing behavior, leading to low precision of formed component. In-planer anisotropy in creep-ageing behavior of a textured Al-Cu-Mg alloy was investigated. The total creep deformation decreased with the increase of the angles between the applied stress and rolling direction. The creep deformation of samples with loading direction parallel to rolling direction is 2.33, 2.07 and 1.62 times greater than that perpendicular to the rolling direction, under 120 MPa, 150 MPa and 180 MPa, respectively. A strong dependence of the anisotropy in creep deformation on the initial textures was suggested, according to the equivalent slid system numbers. With the rise of the external stress, the creep deformation of three different orientation samples increases but the anisotropy of those declines. However, the stress exponent difference among the three orientation samples may be related to the equivalent Schmid factor changes. Although the anisotropy of the mechanical properties in creep aged samples with various orientations is less than 5%, the in-planar anisotropy values of creep deformation under different creep age forming conditions are larger than 30%. It indicated that creep-ageing anisotropy of the studied alloy sheet cannot be ignored in their CAF applications.