轧制变形量对Al-Zn-Mg-Cu合金组织与力学性能以及腐蚀性能的影响

Effect of rolling deformation on microstructure,mechanical and corrosion properties of Al-Zn-Mg-Cu alloy

对Al-Zn-Mg-Cu合金在455~470℃进行均匀化处理，然后在400℃热轧变形（变形量分别为95%、90%和80%），随后进行固溶淬火及 T77时效处理。通过室温力学性能测试、剥落腐蚀实验，结合光学显微镜、扫描电镜、透射电镜和X射线衍射分析，研究轧制变形量对Al-Zn-Mg-Cu合金组织、力学性能以及剥蚀性能的影响。结果表明：热轧变形后，粗大第二相沿轧制方向排列，该相主要是MgZn2相和Al2CuMg相；随变形量从80%增加至95%，固溶时效态合金的再结晶体积分数由5%增加至13%,亚晶尺寸由10μm减小至3μm；变形合金的抗拉强度和屈服强度分别由610 MPa和520 MPa提高到650 MPa和560 MPa，伸长率略有下降；剥落腐蚀和应力腐蚀敏感性增加。

The effect of rolling deformation on microstructure, mechanical properties and corrosion properties of Al-Zn-Mg-Cu alloys were investigated by ambient temperature tensile testing, exfoliation corrosion testing and stress corrosion testing combined with optical microscopy （OM）, scanning electronic microscopy （SEM）, transmission electronic microscopy （TEM） and X-Ray diffraction（XRD）. The results show that the coarsened second particles are chain-like and distribute along the rolling direction after rolling deformation;the mainly second phases are MgZn2 and Al2CuMg. With increasing deformation amount, the volume fraction of recrystallization increases from about 5%to 13%, while the sub grain size decreases from about 10μm to 3μm after solution treatment. The ultimate tensile strength and yield strength increase from 610 MPa and 520 MPa to 650 MPa and 560 MPa, respectively, the elongation decreases slightly, and the exfoliation corrosion and stress corrosion susceptibility increase.