Inhomogeneity of microstructure and mechanical propertiesof 7050-T7651 aluminum alloy thick plate

Abstract

The differences in the microstructure, grain orientation, texture type, aging nano precipitate phase distribution and mechanical properties of 160 mm 7050-T7651 aluminum alloy extra-thick plate at different thickness positions were studied by means of metallographic microscope, scanning electron microscope, transmission electron microscope and mechanical tensile test. The results show that from the surface to the center of the plate, the content of the second phase particles in the microstructure decreases, but the size increases; The surface layer of the plate is mainly composed of small angle grain boundaries. The proportion of small angle grain boundaries ranges from 79% to 85%, while the proportion of small angle grain boundaries in the center of the plate is about 58%, which is a decrease of 26.6% to 31.8% compared to the proportion of small angle grain boundaries on the surface layer of the plate; The surface layer of the plate is mainly characterized by {001}shear texture, accounting for 3.64%. As the thickness increases, the content of deformation texture components gradually increases. The mechanical properties of the plate in the thickness direction show a trend of first decreasing and then increasing along the thickness surface-center-surface direction, and the optimal positions for mechanical properties are all located at the surface of the plate.

Keywords

• 7050-t7651 aluminum alloy thick plate
• microstructure
• texture
• mechanical property
• inhomogeneity