(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083；
2. 湖南人文科技學(xué)院 材料工程系，婁底 417000；
3. 浙江大學(xué) 材料科學(xué)與工程學(xué)院，杭州 310027)
摘 要: 本文提出了一種基于固溶熱軋連續(xù)處理、并通過非對(duì)稱軋制和時(shí)效相結(jié)合的新型熱機(jī)械處理工藝，使Al-Zn-Mg-Cu合金獲得更高的綜合性能，并且利用X射線衍射(XRD)、掃描電鏡(SEM)和透射電鏡(TEM)等微觀分析手段，以及通過拉伸性能測(cè)試、電導(dǎo)率測(cè)試、慢應(yīng)變速率試驗(yàn)(SSRT)等性能測(cè)試方法，研究了新型熱機(jī)械處理對(duì)Al-Zn-Mg-Cu合金微觀組織與性能的影響規(guī)律。結(jié)果表明：經(jīng)過新型熱機(jī)械處理后的合金不僅獲得了良好的強(qiáng)塑性配合，而且具有較好的抗應(yīng)力腐蝕性能；其屈服強(qiáng)度和抗拉強(qiáng)度分別達(dá)到605 MPa和632 MPa，與T6態(tài)的相比分別提高了80 MPa和69 MPa；其電導(dǎo)率介于T6態(tài)和RRA態(tài)的之間，其抗應(yīng)力腐蝕性能均優(yōu)于T6態(tài)的，接近RRA態(tài)的。Al-Zn-Mg-Cu合金良好的強(qiáng)塑性配合得益于位錯(cuò)和納米析出相的協(xié)同作用；同時(shí)，在該新型熱機(jī)械處理?xiàng)l件下，所獲得的不連續(xù)分布晶界析出相及其與位錯(cuò)組態(tài)共同作用提升了合金的抗應(yīng)力腐蝕性能。
關(guān)鍵字: Al-Zn-Mg-Cu合金；熱機(jī)械處理；電導(dǎo)率；抗應(yīng)力腐蝕
（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
