针对航空用Al-Zn-Mg-Cu合金在热力耦合环境下服役的情况，通过热模拟实验研究了预时效处理对Al-Zn-Mg-Cu合金热变形行为的影响。热模拟流变应力曲线显示：在0.01 s^-1低应变速率下，在室温和473 K热变形过程中固溶态合金的流变应力高于时效态，而在573~743 K范围内时效态合金的流变应力超过固溶态，随着温度升高，流变应力差值降低；在0.5 s^-1高应变速率下，固溶态与时效态流变应力差值在743 K异常增大。通过SEM、EBSD和TEM等手段研究了时效态与固溶态Al-Zn-Mg-Cu合金的微观组织演变规律。结果表明，在低应变速率下，473~573 K区间内，时效态Al-Zn-Mg-Cu合金存在的高密度析出相缠结位错，较低的形变储能与较高的热变形激活能抑制基体发生动态回复(DRV)，变形抗力得到提高；673 K时，析出相的不连续粗化和形变储能的提高使时效态Al-Zn-Mg-Cu合金的DRV体积分数大幅提升；743 K时未完全回溶的小尺寸球状颗粒钉扎位错提高了形变储能，促进基体发生动态再结晶(DRX)，使时效态Al- Zn- Mg- Cu合金与固溶态流变应力相近。在高应变速率下，时效态Al-Zn-Mg-Cu合金出现几何动态再结晶，进一步提高了DRX的体积分数，从而降低了时效态Al-Zn-Mg-Cu合金的流变应力。

The effect of pre-ageing treatment on the hot deformation behavior of Al-Zn-Mg-Cu alloys is studied by thermal simulation experiments. Thermal simulation of the flow stress curves showed: at a low strain rate of 0.01s-1, the flow stress is higher than that of the aging state in the solid solution state during hot deformation at room temperature and 473 K, While the flow stress in the aging state exceeds that in the solid solution state at 573K-743K, and the difference of the flow stresses decreases with the increase of the temperature; At a high strain rate of 0.5s-1, the difference between the flow stresses of the solid solution state and the aged state increases abnormally at 743K. The microstructural evolution of the aged and solid solution Al-Zn-Mg-Cu alloys was studied by means of SEM, EBSD, and TEM for the above phenomena, and the results showed: at low strain rate, the high density of precipitates entangled dislocations at 473 K-573 K, the low deformation storage energy and the high thermal deformation activation energy of the aged Al-Zn-Mg-Cu alloys resulted in the un-recovery of the matrix, and the deformation resistance is improved; At 573 K-743 K, the discontinuous coarsening of the precipitates and the increase of deformation storage energy increase the DRV volume fraction of the aged Al-Zn-Mg-Cu alloy, and the small-sized spherical particles of which pinning dislocations increase the deformation storage energy and the volume fraction of DRX as the temperature increases, so that the Al-Zn-Mg-Cu alloy under aged state has a similar flow stress to the solid-solution flow stress. At high strain rates, the appearance of GDRX in the aged Al-Zn-Mg-Cu alloy at high strain rates further increased the volume fraction of DRX, which reduced the flow stress of Al-Zn-Mg-Cu alloys.