Through-thickness texture gradient in an annealed Al-Mg alloy sheet

Abstract

Through-thickness crystallographic texture of a rolled and subsequently annealed Al-Mg continuous cast (CC) alloy was examined. Results showed that the annealed sheet developed a through-thickness texture gradient with the form of a stronger cube texture at the surface when compared to the center layers and varied R orientations through the thickness. While the through-thickness texture gradient was not attributed to the shear related texture, it was still related to the extent of deformation within the sheet.Crystallographic texture is of crucial importance in determining the anisotropy and formability of sheet metals. Cold rolling, the major fabrication step in producing sheet materials, has been shown to result in an inhomogeneous texture through the thickness of sheet metals. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] This textural inhomogeneity typically manifests itself in the formation of relatively strong shear texture components (Table I) on the surface layer, with these components either weakening severely or lacking near the centerline of the sheet. [1][2][3][4][5] While past research has focused primarily on the nonuniform texture of these types of processed sheets, little has been done to investigate sheets produced without the shear-related components at the surface, which can be accomplished through carefully controlled rolling techniques during fabrication. In addition, studies characterizing the developed through-thickness texture of a rolled and subsequently annealed sheet were limited, [12] regardless of the formation of shear textures. Thus, this research was initiated to measure the through-thickness texture developed in both a cold-rolled Al-Mg alloy produced without shear texture components at the surface and this same sheet after annealing.The hot-rolled sheet of a commercial Al-Mg continuous cast (CC) alloy was used in this study. The chemical composition of the sheet, in mass fraction, was 2.40 pct Mg, 0.35 pct Fe, 0.13 pct Si, 0.18 pct Cr, 0.03 pct Mn, 0.02 pct Zn, and balance Al. The as-received hot-rolled sheet was first annealed at 823 K for 7200 seconds followed by water quenching. The next step was to cold roll the sheet at room temperature under good lubricating conditions while avoiding the development of shear texture components at the surface, which was accomplished by maintaining the rolling parameters such that the ratio l/h, where l is the projected length of contact between roll and metals and h is the average of the sheet thickness measured before and after rolling, was between 1 and 5. Multiple passes were carried out to reach a thickness reduction of 70 pct ( ϭ 1.2) resulting in a final sheet thickness of approximately 1.2 mm. The coldrolled samples were then annealed at 673 K for 5500 seconds followed by water quenching.Samples for microstructural examinations were viewed on planes parallel to the longitudinal plane, i.e., the observation plane had a normal that was perpendicular to both the rolling direction (RD) and the normal direction (ND) of the sheet. After m...

Simulation of earing during deep drawing of an Al–3% Mg alloy (AA 5754) using a texture component crystal plasticity FEM

“…The chemical composition is given in Table 1. Since the texture of aluminium alloys is often inhomogeneous through the thickness [37][38][39], the crystallographic texture of the starting sheet was investigated at the surface and in the center layers. Parameter s = a(0.5d) −1 is defined to describe the actual layer position, where a is the distance between the actual layer inspected and the sample center layer, and d the thickness of the sheet, i.e.…”