合金元素对7xxx系铝合金力学性能和晶间腐蚀性能的影响

采用正交试验法研究了Mg、Cu、Zn三种元素对7xxx系合金双级时效后力学性能和晶间腐蚀性能的影响趋势，结果表明：Mg元素的含量对合金强度的影响最大，Zn元素次之，Cu元素的影响最小；Zn元素的含量对合金延伸率和晶间腐蚀深度的影响最大，Cu含量的影响次之，Mg元素的影响最小。为获得最优综合力学性能和晶间腐蚀性能，优化后的合金成分为：Mg1.9%，Cu 0.2%，Zn 6.2%，此合金的屈服强度达到411 MPa，抗拉强度达到437 MPa，延伸率达到15.0 %，晶间腐蚀等级达到2级。

Effect of Elements on Mechanical Property and Intergranular Corrosion Resistance of 7xxx Aluminum Alloy

The effects of Mg, Cu and Zn on the mechanical properties and intergranular corrosion resistance of 7xxx alloy with two-stage aging were studied by orthogonal test. The results show that Mg, Zn and Cu are the first, second and third influencing factors on the strength of 7xxx alloy respectively; Zn, Cu and Mg are the first, second and third influencing factors of alloy elongation and intergranular corrosion depth respectively. In order to obtain the optimal mechanical properties and intergranular corrosion properties, the optimized alloy composition is Mg 1.9 wt%, Cu 0.2 wt%, Zn 6.2 wt%. The yield strength, tensile strength and elongation of the alloy are 411 MPa, 437 Mpa, 15.0 % respectively, and the intergranular corrosion grade is 2.