Abstract: 7050-T7451 aluminum alloy is widely used in aerospace structures, which have the requirements of lightweight and thin wall. As a polycrystalline metal material, the plastic deformation behavior of aluminum alloy presents obvious anisotropy characteristics. Different loading paths will seriously affect the service performance of thin-walled flat-wide parts. Therefore, it is of great significance to deeply analyze the microscopic response mechanism of anisotropy of material mechanical properties. Taking 7050-T7451 aluminum alloy as the research object, combining experiments and X-ray diffraction line analysis methods, the dislocation density value is used to quantitatively characterize and study the movement of dislocations under different spatial angle orientations and different loading conditions. The results show that the grain orientation changes with the deformation process, and there is a phenomenon of (111) crystal plane selective orientation. The range of dislocation density under different loading conditions and forming angles is between 0.275 2×10¹⁴-1.581 8×10¹⁴ m^-2. The dislocation density at different forming angles increases first and then decreases with the increase of strain rate, and there is a significant difference with temperature changes. Under different loading conditions, the dislocation density in the forming angle range of 0°-90°shows a trend of first decreasing, then increasing, then decreasing and increasing. When the forming angle is 45åt room temperature, the dislocation density reaches the maximum of 1.581 8×10¹⁴ m^-2. The research on the micro-deformation mechanism of 7050-T7451 aluminum alloy can better grasp the anisotropic deformation behavior of the material and provide theoretical support for its engineering application in the aerospace field.

Key words: aluminum alloy 7050-T7451, anisotropy, dislocation density, X-ray diffraction