Effect of aging time on precipitation behavior, mechanical and corrosion properties of a novel Al-Zn-Mg-Sc-Zr alloy  

时效时间对一种新型Al-Zn-Mg-Sc-Zr合金析出行为、力学和腐蚀性能的影响（英文）

作　　者：李波[1] 潘清林[2] 陈从平[1] 尹志民[2] 

机构地区：[1]三峡大学机械与动力学院,宜昌443002 [2]中南大学材料科学与工程学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2016年第9期2263-2275,共13页中国有色金属学报（英文版）

基　　金：Project(2012CB619503)supported by the National Basic Research Program of China;Projects(51475266,51005134)supported by the National Natural Science Foundation of China

摘　　要：The precipitation behavior, mechanical properties and corrosion resistance of a novel Al-Zn-Mg-Sc-Zr alloy aged at different time were studied by optical microscopy（OM）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, tensile tests, potentiodynamic polarization and electrochemical impedance spectroscopy. The results revealed that with increasing aging time at 120 ℃, the hardness and tensile strength of the alloy increased rapidly at first and then slightly decreased. The resistance of exfoliation corrosion（EXCO） and intergranular corrosion（IGC） increased gradually with increasing aging time. The same trend of corrosion properties was demonstrated by electrochemical polarization curves and EIS test. The characteristics of grain boundary precipitates and precipitate free zone（PFZ） had a significant influence on the mechanical and corrosion behaviors of the studied alloy. On the basis of TEM observations, the size of grain boundary precipitates and the width of PFZ became larger, and the distributed spacing of grain boundary precipitates was enhanced with increasing aging time.通过光学显微镜、扫描电镜、透射电镜、拉伸实验、极化曲线和电化学阻抗谱等方法研究时效时间对一种新型Al-Zn-Mg-Sc-Zr合金析出行为、力学和腐蚀性能的影响。结果表明:当合金经过120°C时效时,随着时效时间的延长,合金的硬度和拉伸强度呈先快速增加后逐渐降低的趋势。同时,合金的抗剥落腐蚀和晶间腐蚀性能随着时效时间的延长逐渐提高,与极化曲线和电化学阻抗谱呈现的趋势保持一致。合金的晶界析出行为和无沉淀析出带对其力学和腐蚀行为有着重要的影响。由透射电镜观察到的组织可知,随着时效时间的延长,晶界析出相逐渐粗化,无沉淀析出带变宽,且晶界析出相间距变大。

关 键 词：aluminum alloy heat treatment precipitation behavior Al3（Sc Zr） particles electrochemical impedance spectroscopy 

分 类 号：TG166.3[金属学及工艺—热处理] TG146.21[金属学及工艺—金属学]