Wrought aluminum alloy with gradient structure and preparation method of wrought aluminum alloy

The invention relates to a wrought aluminum alloy with a gradient structure and a preparation method of the wrought aluminum alloy, and belongs to the field of wrought aluminum alloy manufacturing, and the wrought aluminum alloy comprises the following substances in percentage by mass: 5.0-7.0% of Zn, 2.0-3.0% of Mg, 0.5-1.0% of Cu, 0.3-0.6% of Er, 0.2-0.5% of Cr and the balance of Al and impurities. A small amount of rare earth and other precious elements are added into the aluminum alloy, the aluminum alloy structure is refined, the elongation of the material is greatly improved, the performance of the material is improved, the anisotropy is improved under the condition that the cost of the material is slightly improved, equipment used in the toughening technology is common equipment in normal aluminum alloy machining, the machining period is short, and the machining cost is low. The operation is simple and safe, and large-scale industrial application is facilitated. 一种具有梯度结构变形铝合金及其制备方法，属于变形铝合金制造领域，包括如下质量百分