Al-5.9Zn-2.4Mg-1.6Cu合金的热处理与组织性能研究  

Study on heat treatment and microstructure properties of high strength Al-5.9Zn-2.4Mg-1.6Cu alloy

作　　者：马丽[1] 蒋小盼[1] MA Li;JIANG Xiao-pan(Engineering and Technology odlege Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]湖北工业大学工程技术学院,湖北武汉430068

出　　处：《轻合金加工技术》2021年第11期39-46,共8页Light Alloy Fabrication Technology

基　　金：教育部科技发展中心高校产学研创新基金-“北创助教”基金(2018A0503)

摘　　要：研究了不同回归温度处理和不同激光功率处理对Al-5.9Zn-2.4Mg-1.6Cu合金物相组成、显微组织和电化学性能的影响。结果表明:回归温度160℃~240℃、激光功率550 W~750 W时,Al-5.9Zn-2.4Mg-1.6Cu合金主要由ɑ-Al、η′和η(MgZn_(2))相组成;回归温度200℃时,晶界处断续分布着尺寸约20 nm的析出相和宽度约15 nm的无沉淀析出带(PFZ);激光处理代替回归处理,激光功率650 W时,晶界析出相呈断续颗粒状(大小约20 nm)分布,PFZ宽度约2 nm。随着回归温度从160℃上升至240℃,合金的腐蚀电位先正向移动后负向移动,腐蚀电流密度先减小后增大,溶液电阻和电荷转移电阻先增加后减小,回归温度为200℃时耐蚀性最好。随着激光功率从550 W增加至750 W,合金的腐蚀电位先负向移动后正向移动,腐蚀电流密度先减小后增大,激光功率650 W时合金的耐蚀性最好,溶液电阻和电荷转移电阻先增加后减小。相较于激光功率650 W,回归温度200℃时合金的腐蚀电位更负,腐蚀电流密度更大,前者具有更优的耐蚀性能,这主要与合金中晶界断续颗粒状析出相与较宽的PFZ形成有关。The effects of different regression temperatures and laser powers on the phase composition, microstructure and electrochemical properties of Al-5.9 Zn-2.4 Mg-1.6 Cu alloy were studied. The results show that Al-5.9 Zn-2.4 Mg-1.6 Cu alloy is mainly composed of α-Al, η′ and η(MgZn_(2)) phase at the regression temperature of 160 ℃-240 ℃ and the laser power of 550 W-750 W;at the regression temperature of 200 ℃, the precipitated phases with the size of about 20 nm and PFZ with the width of about 15 nm are intermittently distributed at the grain boundary. When the regression treatment is replaced by laser treatment and the laser power is 650 W, the precipitated phase is in the form of intermittent particles(about 20 nm) and the width of PFZ is about 2 nm. With the regression temperature increasing from 160 ℃ to 240 ℃, the corrosion potential of the alloy moves first forward and then negatively;the corrosion current density decreases first and then increases;the solution resistance and charge transfer resistance first increase and then decrease. The corrosion resistance is the best when the regression temperature is 200 ℃. With the increase of laser power from 550 W to 750 W, the corrosion potential of the alloy first moves negatively and then positively;the corrosion current density decreases first and then increases;the solution resistance and charge transfer resistance first increase and then decrease, and the corrosion resistance is the best when the laser power is 650 W. Compared with the alloy with 650 W laser power, the corrosion potential of the alloy at 200 ℃ is more negative and the corrosion current density is higher;the former has better corrosion resistance, which is mainly related to the formation of discontinuous granular precipitates and wider PFZ.

关 键 词：Al-5.9Zn-2.4Mg-1.6Cu合金 回归温度 激光功率 显微组织 电化学性能 

分 类 号：TG166.3[金属学及工艺—热处理]