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采用硬度、电导率测试、金相及透射电镜观察等手段,研究回归处理工艺对7050铝合金力学和晶间腐蚀性能的影响。研究结果表明:T6态合金硬度和强度很高,但抗晶间腐蚀能力较弱;与T6态相比,合金经较低温度长时间回归并再时效后,强度和抗晶间腐蚀性能都得到改善;合金经120℃/20 h预时效+190℃/60 min回归+120℃/24 h再时效处理后,其抗拉强度、屈服强度、伸长率和晶间腐蚀最大深度分别为593 MPa,571 MPa,10.5%和0.05 mm,具有最佳的综合性能;经190℃/60 min回归和再时效处理后,合金晶内组织与T6态的组织相似,晶界析出相粗大且不连续分布,因此,合金强度最高,抗晶间腐蚀能力最强。
The effects of regressive treatment on the mechanical and intergranular corrosion properties of 7050 aluminum alloy were studied by means of hardness, electrical conductivity test, metallography and transmission electron microscopy. The results show that the hardness and strength of T6 alloy are very high, but their resistance to intergranular corrosion is weaker. Compared with T6, the strength and intergranular corrosion resistance of alloy are obtained after regaining and re-aging at lower temperature And the maximum depth of tensile strength, yield strength, elongation and intergranular corrosion of the alloy after aging at 120 ℃ / 20 h, reheating at 190 ℃ / 60 min and reheating at 120 ℃ / 24 h were 593 MPa , 571 MPa, 10.5% and 0.05 mm respectively. After 190 ℃ / 60 min regression and re-aging treatment, the microstructure of the alloy is similar to the T6 microstructure, and the grain boundary precipitates are coarse and discontinuous , Therefore, the highest alloy strength, the strongest resistance to intergranular corrosion.