预拉伸对7050铝合金腐蚀性能的影响.pdf

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1、第44卷第5期中南大学学报(自然科学版)、，01．44NO．52013年5月JournalofCentralSouthUniversity(ScienceandTechnology)Mav2013预拉伸对7050铝合金腐蚀·I,土／4-Z月~匕的影响宋丰轩，张新明，刘胜胆，韩念梅，花隆(中南大学材料科学与工程学院，湖南长沙，4100831摘要：通过硬度、电导率、Tafel极化曲线、慢应变速率拉伸测试及光学显微镜、透射电镜组织观察，研究预拉伸变形量对7050铝合金板材强度和腐蚀性能的影响。研究结果表明：预拉伸引入大量位错，在时效过程中促进平衡相的形核；随着预拉伸变形量的增大，

2、晶内相增多、粗化，合金的强度降低，电导率升高；随着预拉伸变形量增大，合金内的位错密度增大，空位浓度降低，晶界析出相间距先增大后减小，抗腐蚀性能先增大后减小；无沉淀析出带(PFZ)先变宽后消失，抗腐蚀性能先减小后增大；综合晶界析出相的分布和PFZ宽度的共同影响，随着预拉伸变形量的增大，板材的抗腐蚀性能先逐渐减小后迅速降低。关键词：7050铝合金；预拉伸；腐蚀性能；微观组织中图分类号：TG146．2文献标志码：A文章编号：1672—7207(2013)05—1791—07Effectsofpre—stretchingoncorrosionresistanceof7050alum

3、inumalloySONGFengxuan，ZHANGXinming，LIUShengdan，HANNianmei，HUALong(SchoolofMaterialsScienceandEngineering，CentralSouthUniversity,Changsha410083，China)Abstract：Theeffectsofpre—stretchingonstrength，corrosionresistanceandmicrostructureof7050aluminumalloyplatewerestudiedbyhardness，electricalcon

4、ductivity,Tafelcurves，slowstrainratetensile(SSRT)，opticalmicroscopyandtransmissionelectronmicroscopytests．Theresultsshowthatmanydislocationsaregeneratedintheprocessofpre—stretching，andthedislocationscanprovideeficientnucleationsitesfor叩phaseduringtheaging．Withtheincreaseofthepre—stretching

5、deformation，thenumberandsizeofthephasewithingrainsincreases，whichresultsinthereductioninthemechanicalstrengthandimprovementintheelectricalconductivity．Asthedensityofdislocationsincreases，thevacancyconcentrationdecreases，whichmakesthedistancebetweenprecipitatesatgrainboundariesbecomerelativ

6、elylagerfirst，andthenreduce，andthecorrosionresistanceimprovefirst，andthendecrease．Meanwhile，precipitate—freezones(PFZ)becomewiderfirst，andthengraduallydisappearwiththeincreaseofthepre—stretchingdeformation，whichcausesthecorrosionresistancetodecreasefirst。andthenimprove．So。undertheinfluence

7、oftheprecipitatesatgrainboundariesandthePFZtogether,thecorrosionresistancegraduallydecreasesfirst，andthendecreasesquicklywiththeincreaseofthepre—stretchingdeformation．Keywords：7050aluminumalloy；pre—stretching；corrosionresistance；microstructure7050铝合金由于淬火敏感性低、综