中文摘要：

采用硬度与电导率测试、拉伸试验、金相（OM）观察、X射线衍射（XRD）分析、晶间腐蚀和剥落腐蚀（EXCO）试验,研究了不同热处理工艺（固溶-T6时效,固溶-预压缩-T6时效,预回复-固溶-预压缩-T6时效和预回复-固溶-预压缩-T76时效）对含锆锶复合微合金化的Al-10.78Zn-2.78Mg-2.59Cu-0.221Zr-0.0465Sr高强铝合金组织与性能的影响。结果表明：在T6（120℃×24 h）时效制度下,预回复和预压缩均能提高位错强化,并且预回复能显著抑制再结晶;与固溶-预压缩-T6相比,预回复-固溶-预压缩-T6工艺能在不降低强度的情况下,提高抗晶间和剥落腐蚀性能（最大晶间腐蚀深度从125μm减少到91μm,剥落腐蚀从EB级提高到EA级）;预回复-固溶-预压缩-T76状态下,合金强度低至600 MPa,但电导率高达31.58%ICAS,较T6时效下的抗腐蚀性能明显改善。经研究表明,Al-10.78Zn-2.78Mg-2.59Cu-0.221Zr-0.0465Sr高强铝合金挤压材在预回复-固溶-预压缩-T6时效工艺下的综合性能最佳。

英文摘要：

The effect of solid solution-T6, solid solution-pre-compression-T6, pre-recovery-annealing-solid solution-T6 and pre-recov- ery-annealing-solid solution-pre-compression-T76 aging treatment on microstructure and mechanical properties of the experimental high strength AI-10.78Zn-2.78Mg-2.59Cu-0.221Zr-0. 0465Sr aluminum alloy extrusions were investigated by hardness and electrical con- ductivity tests, tensile test, optical microscope （OM）, X-ray diffraction （XRD） analysis and corrosion experiment. The results showed that under the T6 （ 120℃ × 24 h） aging treatment system, pre-recovery-annealing and pre-compression could improve the dislocation strengthening, and pre-recovery-annealing could significantly inhibit recrystallization. Compared with the solid solution-precompression-T6, pre-recovery-annealing-solid solution-pre-compression-T6 process could improve the corrosion resistance （the maximum corrosion depth was reduced from 125 to 91 μm, exfoliation corrosion rating increased from EB to EA） without reducing the strength. Under the condition of pre-recovery-annealing-solid solution-pre-compression-T76 aging treatment, the strength of the alloy was as low as 600 MPa, but the electrical conductivity reached as high as 31.58% ICAS, which significantly improved the corrosion resistance compared to T6 aging treatment. Studies showed that the experimental high-strength aluminum alloy extrusion presented the optimal comprehensive performance under the condition of pre-recovery-annealing-solid solution-pre-compression-T6.