组织超细化对ZK60镁合金腐蚀行为的影响  

Effect of Grain Ultrafining on Corrosion Behavior of ZK60 Mg Alloy

作　　者：李鑫[1] 江静华[2,3] 赵永好[1] 文道静 

机构地区：[1]南京理工大学材料科学与工程学院,南京210094 [2]河海大学力学与材料学院,南京210098 [3]江苏省先进微纳米材料及装备协同创新中心,南京210094

出　　处：《腐蚀与防护》2015年第11期1030-1037,1042,共9页Corrosion & Protection

基　　金：江苏省自然科学基金(BK20131373)

摘　　要：借助等通道转角挤压(ECAP)模具制备了超细晶ZK60镁合金,结合时效处理调控了合金中第二相的分布形态,采用局部电化学阻抗谱(LEIS)结合浸泡试验,分析了组织超细化及小尺度第二相对ZK60镁合金电化学腐蚀行为的影响。结果表明,固溶态ZK60镁合金在3.5%NaCl溶液中的失重速率随着ECAP加工道次的增加而增加;随着浸泡时间的增加,超细晶合金的局部阻抗先增加后下降;后续时效处理使样品中残余应力下降、第二相重新分布,从而提高了表面腐蚀产物对基体的保护作用,改善了超细晶镁合金的耐蚀性。Ultra-fine grained ZK60 Mg alloy was obtained by equal channel-angular pressing （ECAP）, and the distribution of second phases was further adjusted by post-aging. Subsequently, localized electrochemical impedance spectroscopy （LEIS） and constant immersion test were used to analyze the influence of grain refinement and finer second-phase particles on the corrosion behavior of ZK60 Mg alloy. The results showed that the mass 10ss rate of the solution-treated ZK60 Mg alloy in 3. 5GNaCl increased with ECAP passes, and the impedance first increased and then decreased with immersion time. Corrosion behavior of ultra fine-grained ZK60 Mg alloy was improved by post-ECAP aging, due to the better protective ability of corrosion product after the relief of internal stress and the redistribution of second phase.

关 键 词：镁合金 超细晶 等通道转角挤压 微区电化学 

分 类 号：TG174.4[金属学及工艺—金属表面处理] TG146.2[金属学及工艺—金属学]