采用光学显微镜、扫描电镜、透射电镜、拉伸试验、剥落腐蚀试验等分析方法,研究了不同固溶、时效处理制度对含钪7085铝合金(Al-7.5Zn-1.5Mg-1.4Cu-0.15Zr-0.15Sc)强度和剥落腐蚀性能的影响.结果表明:与常规固溶处理和双级固溶处理相比,强化固溶可使合金中粗大相溶解更充分,晶粒细化,同时提高合金强度和剥落腐蚀性能;在T6、T76、回归再时效3种时效状态下,T76时效后合金的强度和剥落腐蚀抗性最好,这与形成的粗大不连续的晶界析出相有关.含钪7085铝合金最佳固溶时效制度为:强化固溶(450℃×1 h+460℃×2 h+475℃×2 h)+T76时效(120℃×5 h+160℃×7h)处理.
Effects of different solid solution treatments and aging treatments on strength and exfoliation corrosion properties of 7085 aluminum alloy containing Sc (A1-7.5Zn-l.5Mg-l.4Cu-0.15Zr-0.15Sc) were investigated,and mechanical properties and exfoliation corrosion properties of the alloy were analyzed by tensile tests and exfoliation corrosion tests,respectively,microstructure was studied by means of optical microscope(OM),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results show that compared with conventional solid solution and two-stage solution,the enhanced-solid-solution(450 ℃ × 1 h + 460 ℃ × 2 h + 475 ℃ × 2 h) can make the precipitated phase dissolve completely and refine the grain,and the strength and exfoliation corrosion resistance of the alloy are improved.Compared with the T6 aging and retrogression and re-aging treatments,the strength and exfoliation corrosion resistance of the alloy are the best after T76 aging treatment,which is related to the formation of coarse discontinuous grain boundary precipitated phases.The optimal solution-aging treatments for the 7085 aluminum alloy containing Sc are enhanced-solid-solution (450 ℃ ×1 h+460 ℃ ×2 h+475 ℃ ×2 h) +T76 aging (120 ℃ ×5 h+160 ℃ ×7 h).
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