回归再时效温度对Al-Zn-Mg合金性能的影响

Effects of the Temperature in RRA on Al-Zn-Mg Alloy

摘要: 通过电导率、硬度、拉伸、电化学腐蚀以及透射分析等实验，研究了回归再时效(RRA)中预时效温度和第三级时效温度的改变对Al-Zn-Mg铝合金型材的力学性能和电化学腐蚀性能的影响。研究了其两个阶段温度的变化对实验结果产生的相互作用以及对实验结果产生的影响。结果表明：110℃/24 h + 185℃ /105 min + 120℃/24 h合金拉伸强度最高，腐蚀性能一般。110℃/24 h + 185℃/105 min + 150℃/24 h合金耐腐蚀性能最好，但拉伸强度最差；较高的预时效温度会加快晶内析出η相，回归时效时不能溶解η相，从而加速合金在第三级时效产生过时效，获得较好的耐腐蚀性能。

Abstract: Through the test of conductivity, hardness, tensile strength, electrochemical corrosion and TEM, the effect of mechanical properties and electrochemical corrosion properties of the Al-Zn-Mg aluminum during preaging and the third step aging in Retrogression and Re-ageing was investigated. The effect of the result between the different temperatures in preaging and third step aging was studied. The results show that after the treatment of 110˚C/24 h + 185˚C/105 min + 120/24 h, the tensile strength of the alloy is the highest, but the electrochemical corrosion property is bad. After the treatment of 110˚C/24 h + 185˚C/105 min + 150˚C/24 h, the electrochemical corrosion property is the best while the tensile strength is the worst. The higher preaging temperature could accelerate the precipitation reaction of η which won’t be dissolved in retrogression; it accelerates the alloy to over aging to obtain better corrosion resistance.