研究7050铝合金型材在固溶淬火与分级时效各阶段亚晶界的演变，阐明亚晶界形成与晶粒内取向梯度的关系。结果表明：固溶淬火后长轴为200μm、短轴为80μm的纺锤状粗晶组织经过(121℃，360 min)+(177℃，60 min)双级时效处理后，被分割碎化成20μm左右的等轴状细小亚晶组织。电子背散射衍射技术(EBSD)证实碎化由小角度晶界分割造成，且固溶淬火后晶面的弯曲程度经时效后降低了77.8%。透射电镜(TEM)结果表明，时效过程使淬火散乱位错逐步形成位错列和小角度晶界。二级时效时MgZn 2相在亚晶界上析出，促进了Graff试剂的侵蚀效果，使得在光学显微镜(OM)下可观察到亚晶界。%The evolution of sub-grain boundaries of 7050 Al alloy profiles during solution quenching and interrupted aging treatment was studied, and the relationship between formation of the sub-grain boundaries and the orientation gradient was clarified. The results show that the spindle-shaped grains with 200μm in length and 80μm in width after solution quenching break into fine equiaxed sub-grains with average diameter of about 20 μm after duplex aging at (121 ℃, 360 min) and (177 ℃, 60 min). EBSD analysis demonstrates that grain refinement results from the segmentation of coarse grains by low angle grain boundaries and the lattice curvature due to solution quenching decreases by 77.8%after aging treatment. The investigation of TEM shows that the scattered dislocations by quenching arrange into dislocation arrays and low angle grain boundaries with aging time. MgZn 2 precipitates on the sub-grain boundary, which helps the etchant Graff to visualize the sub-grain boundary using OM in the secondary aging.
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