(1. 中南大学 材料科学与工程学院，长沙 410083；
2. 湖南人文科技学院 材料工程系，娄底 417000；
3. 浙江大学 材料科学与工程学院，杭州 310027)
摘 要: 本文提出了一种基于固溶热轧连续处理、并通过非对称轧制和时效相结合的新型热机械处理工艺，使Al-Zn-Mg-Cu合金获得更高的综合性能，并且利用X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等微观分析手段，以及通过拉伸性能测试、电导率测试、慢应变速率试验(SSRT)等性能测试方法，研究了新型热机械处理对Al-Zn-Mg-Cu合金微观组织与性能的影响规律。结果表明：经过新型热机械处理后的合金不仅获得了良好的强塑性配合，而且具有较好的抗应力腐蚀性能；其屈服强度和抗拉强度分别达到605 MPa和632 MPa，与T6态的相比分别提高了80 MPa和69 MPa；其电导率介于T6态和RRA态的之间，其抗应力腐蚀性能均优于T6态的，接近RRA态的。Al-Zn-Mg-Cu合金良好的强塑性配合得益于位错和纳米析出相的协同作用；同时，在该新型热机械处理条件下，所获得的不连续分布晶界析出相及其与位错组态共同作用提升了合金的抗应力腐蚀性能。
关键字: Al-Zn-Mg-Cu合金；热机械处理；电导率；抗应力腐蚀
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Department of Materials Engineering, Hunan University of Humanities, Science and Technology, Loudi 417000, China;
3. School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China）
Abstract:This paper proposed a novel thermomechanical treatment process based on the solid solution hot rolling, asymmetric rolling and aging, to achieve better comprehensive performance of Al-Zn-Mg-Cu alloy. The effect of novel thermomechanical treatment (NTMT) on the mechanical properties and stress corrosion cracking (SCC) resistance of Al-Zn-Mg-Cu alloy were investigated by methods including tensile testing, conductivity testing, slow strain rate testing (SSRT), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the alloys treated by NTMT not only obtain excellent combination of strength and plasticity, but also have good stress corrosion resistance. The highest yield strength and ultimate tensile strength reach 605 MPa and 632 MPa, respectively, which are increased by 80 MPa and 69 MPa compared with that of T6 state. The conductivities of TMT samples are between those of T6 and RRA states, and the SCC resistances are better than that of T6 state, close to that of RRA state. The comprehensive properties of Al-Zn-Mg-Cu alloy are enhanced by the synergistic effect of the configuration of dislocations and nano-precipitated phases. At the same time, this process enables the alloy to obtain discontinuously grain boundary precipitates which work together with the dislocation configuration to improve the SCC resistance of Al-Zn-Mg-Cu alloy.
Key words: Al-Zn-Mg-Cu alloy; thermomechanical treatment; conductivities; stress corrosion resistance
