中文摘要：

采用硬度与电导率测试、拉伸试验、晶间腐蚀和剥落腐蚀试验以及X射线衍射（XRD）、扫描电镜（SEM）、电子背散射衍射（EBSD）分析等方法研究预变形对Al-12.45Zn-3.56Mg-1.12Cu-0.21Zr-0.0553Sr铝合金挤压材组织与性能的影响。结果表明:该合金在（121℃,24 h）时效制度下,预变形处理能有效引入位错,位错密度从0.197×10-14m-2提高到1.156×10-14m-2;同时,由于位错对强度的贡献高达58.7 MPa。根据EBSD分析,经预变形处理后,合金的低角度晶界所占比例为66.2%,比未经预变形处理的合金提高12.6%,平均晶界角度值降低3.894°,平均晶粒尺寸增长6.396mm。预变形能够明显提高合金的抗晶间腐蚀性能（最大晶间腐蚀深度由222.1mm降低至165mm）,对剥落腐蚀性能的影响不明显。

英文摘要：

The effects of pre-deformation on microstructure and properties of Al-12.45Zn-3.56Mg-1.12Cu-0.21Zr-0.0553Sr ultra-high strength aluminum alloy extrusion materials were studied by means of micro-hardness tester and electrical conductivity test, tensile test, intergranular and exfoliation corrosion experiment, X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD) analysis. The results show that in the aging system at 121℃ for 24 h, the pre-deformation can effectively introduce dislocations, the dislocation density increases from 0.197×10?14m?2to 1.156×10?14 m?2, and the strength reaches up to 58.7 MPa because of the dislocation contribution. Based on EBSD analysis, after pre-deformation treatment, the low angle grain boundary proportion (66.2%) of the pre-deformation alloy increases by 12.6% than that of the underformed alloy, the mean misorientation value reduces 3.894°, and the average grain size increasesby 6.396 μm. The pre-deformation treatment can significantly improve the intergranular corrosion resistance properties (the maximum intergranular corrosion depth reducing from 222.1 μm to 165 μm), but little improvement on exfoliation corrosion performance.