High-damage tolerance type ultrahigh strength aluminum alloy and preparation method thereof

The present invention relates to a high-damage tolerance type ultrahigh strength aluminum alloy and a preparation method thereof. The high-damage tolerance type ultrahigh strength aluminum alloy comprises the following components in percentage by weight: 8.5-10.0 percent of Zn, 1.0-2.5 percent of Mg, 1.0-2.0 percent of Cu, 0.06-0.20 percent of Zr, 0.02-0.05 percent of Ti, not more than 0.08 percent of Fe, not more than 0.06 percent of Si and the balance of Al and unavoidable impurities, wherein the Fe content is larger than Si content. The method comprises the following steps: firstly, smelting and casting; then carrying out homogenization on an alloy casting blank by stages, carrying out hot rolling on the homogenized casting blank and carrying out solid dissolution on a hot rolled plate; prestretching the plate in four hours after quenching; and finally immediately carrying out double-stage ageing processing on the prestretched plate. The obtained alloy has higher strength and damage tolerance and is suitab