Low-density and low-quenching-sensitivity Al-Zn-Mg-Cu series aluminum alloy

The invention discloses low-density and low-quenching-sensitivity Al-Zn-Mg-Cu series aluminum alloy. The alloy is characterized in that the mass ratio of alloy elements of the Al-Zn-Mg-Cu alloy is adjusted. The low-density and low-quenching-sensitivity Al-Zn-Mg-Cu series aluminum alloy comprises the following components in percentage by weight: 4.5 to 6.5 percent of zinc, 4.0 to 5.0 percent of magnesium, 0.5 to 1.0 percent of copper, 0.08 to 0.15 percent of zirconium, less than 0.06 percent of titanium, less than 0.3 percent of silicon, less than 0.3 percent of iron, less than 0.15 percent of manganese and the balance of aluminum. The novel aluminum alloy adopts proper homogenization system and pressure processing, and has high strength, good plasticity, low density and low quenching sensitivity after solid solution and aging. According to a material (part) prepared from the alloy, the strength is more than 540 Mpa after peak aging; the room-temperature extension rate is not less than 10 percent; the Vickers