摘要
利用扫描电镜(SEM)、透射电镜(TEM)、差示扫描量热法(DSC)、硬度和导电率检测、浸泡腐蚀实验研究了固溶参数和淬火冷却速率对7055铝合金微观组织和性能的影响。研究结果显示原始态合金中存在明显的粗大未溶相,其面积分数为23.8%。经过450℃/1 h单级固溶后粗大未溶相的面积分数降低至7.6%。经过450℃/1 h+475℃/1 h双级固溶,未溶相的面积分数进一步降低至4.3%,当第二级固溶温度升高至490℃时发生过烧。合金的硬度和导电率在固溶处理后均有所下降,之后经过160℃/6 h时效后显著上升。淬火冷却速率对合金脱溶和耐腐蚀性能具有重要影响,当冷却速率小于30℃/min时脱溶析出η相和S相,降低后续时效析出驱动力。合金的淬火敏感温度区间约为375~200℃,以不低于60℃/min的冷却速率经过此温度区间可以显著抑制脱溶析出。
The effect of solid solution parameter and quenching cooling rate on the microstructure and properties of the 7055 aluminum alloy was studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),differential scanning calorimetry(DSC) and hardness,electrical conductivity,immersion corrosion test methods.The results show that there is obvious coarse phase aggregation in the as-extruded alloy,with an area fraction of 23.8%;after single-stage solid solution at 450 ℃/1 h,the coarse phase redissolves obviously,with an area fraction of 7.6%;the coarse phase is further reduced after the double-stage solution at 450 ℃/1 h+475 ℃/1 h,and the area fraction is reduced to 4.3%.When the second stage solution temperature is increased to 490 ° C,the alloy is overburnt.The hardness and electrical conductivity of the alloy decrease after different solid solution treatments,and then increase significantly after aging treatment at 160 ℃/6 h.The quenching cooling rate has a significant effect on exsolution and corrosion resistance.The alloys with cooling rates of less than 30 ℃/min have obvious exsolution of η phase and S phase,which reduce the driving force of subsequent aging precipitation.The quenching sensitive temperature range of the alloy is around 375-200 ℃,and the exsolution during cooling can be significantly suppressed by passing through the quenching sensitive temperature range with cooling rates of not less than 60 ℃/min.
作者
赵辉
程全士
赵言
康元
张文静
叶凌英
ZHAO Hui;CHENG Quan-shi;ZHAO Yan;KANG Yuan;ZHANG Wen-jing;YE Ling-ying(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Guangdong Haomei Technology Research Institute Co.,Ltd.,Qingyuan 511540,China;Tianjin Key Laboratory of Fastening Technology,Tianjin 300300,China;Aerospace Precision Production Co.,Ltd.,Tianjin 300300,China)
基金
Project(2022YFB3403700) supported by the National Key R&D Program of China
Project(2022DZX006) supported by the Science and Technology Special Fund Project of Qingyuan City,China。
作者简介
Corresponding author:YE Ling-ying,PhD,Professor,E-mail:lingyingye@csu.edu.cn。
