Analysis of empirical relation between microstructure, texture evolution and fatigue properties of an Al-Cu-Li alloy during different pre-deformation processes

The microstructure and fatigue properties of Al-Cu-Li alloy sheets were investigated respectively under the conditions of without pre-deformation, 3% pre-stretching deformation and 8% pre-rolling deformation utilizing scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) in present work. Results show that the intensive Goss texture and relatively weaker Brass, Cube texture were formed in without pre-deformed alloy after aging treatment. The pole density level of Goss texture was decreased remarkably and the intensity of Brass, Cube texture was increased lightly after 3% pre-stretching deformation and 8% pre-rolling deformation. The magnitude order of fatigue crack propagation (FCP) rate of the alloy under different pre-deformation conditions was da/dN (pre-rolling) > da/dN (pre-stretching) > da/dN (non- predeformanon) in stage II (Paris regime). The combined contribution of T-1 phase with different size, amount and the intensity of Goss texture is the main factors affecting the FCP rate of Al-Cu-Li alloy.