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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。
The effects of aging time on the precipitation behavior, mechanical properties and corrosion resistance of a novel Al-Zn-Mg-Sc-Zr alloy were investigated by optical microscope, scanning electron microscope, transmission electron microscope, tensile test, polarization curve and electrochemical impedance spectroscopy . The results show that when the alloy is aged at 120 ° C, the hardness and tensile strength of the alloy decrease first and then decrease with the aging time increasing. At the same time, the anti-spalling and intergranular corrosion resistances of the alloys gradually increase with the aging time, which is in agreement with the polarization curve and electrochemical impedance spectroscopy. The grain boundary precipitation behavior and precipitation-free zone have an important influence on the mechanical and corrosion behavior of the alloy. The microstructure observed by transmission electron microscopy shows that as the aging time prolongs, the grain boundary precipitates gradually coarsen, and the precipitation-free zone broadens without separation and the grain-boundary precipitates become larger.