Microstructure and tensile properties of industrially prepared 7050 aluminum alloy thick plate

The microstructure and tensile property of industrially prepared 7050 aluminum alloy thick plate were investigated by means of optical microscopy (OM), transmission electron microscopy (TEM) and tensile test. The distribution of grain size in the alloy was uneven, with parts of coarse grains. The size and quantity of coarse grains and the degree of grain size inhomogeneity in the central layer were higher than those in the surface and quarter layer. After the two-step aging, the main precipitation phases of the alloy were η phase, phase and a small amount of GPⅡ region. Discontinuous precipitation and precipitation free zone (PFZ) was found in the grain boundaries. The precipitation density in the surface layer was greater than that in the quarter and center layer. The gradient distribution of the hardness and tensile properties along with the thickness direction were found. The strength, hardness and elongation in the surface were higher than those in the quarter and center layer.