中文摘要：

采用电子拉伸试验机、光学显微镜（OM）、显微硬度计、扫描电子显微镜（SEM）、能谱（EDS）等手段，对Al-Zn—Mg铝合金不同固溶温度下时效前后的显微组织与性能进行了研究。结果表明，时效前随固溶温度的提高，第二相的固溶效果加强，过剩第二相的强化效果降低，且回复和再结晶的程度也加强，所以其强度和硬度不断降低。时效后的强度和硬度明显高于时效前，且经743K×70min同溶的合金再经393K×50h时效后硬度、抗拉强度、屈服强度分别达到118HV0．1、347．0MPa和286．1MPa，相对原始材料分别提高9.3％、3．6％和5．9％。

英文摘要：

The microstructure and properties of Al-Zn-Mg alloy non-aged and aged at different solid solution temperature were investigated by means of electronic tensile machine, microhardness tester, optical microscope （OM）, scanning electron microscopy （SEM） and energy dispersive X-ray spectrometer （EDS）. The results show that the solid solubility of the second-phase increases with the increase of solution temperature before aging, the strengthening of the second phase decreases. The reversion and recrystallization also increase with the increase of solution temperature, therefore, the strength and microhardness of Al-Zn-Mg alloy decrease. The strength and microhardness of Al-Zn-Mg alloy after aging are evidently higher than those before aging, and the samples solution-treated at 743 K for 70 min and aged at 393 K for 50 h are of the highest strength and microhardness, Its microhardness, tensile strength, yield strength and elongation is up to 118 HV0.1,345.5 MPa and 286.1 MPa, respectively, which are higher than those of the original alloy by 9.3%, 3.6% and 5.9%.