2195铝锂合金摩擦搅拌焊接头组织与腐蚀行为  

Structure and corrosion behavior of friction stir weld joint of 2195 Al-Li alloy

作　　者：马云龙[1,2] 杨子奇 李劲风 MA Yunlong;YANG Ziqi;LI Jinfeng(Central South University,Changsha 410083,China;Beijing Institute of Aerospace Systems Engineering,Beijing 100076,China)

机构地区：[1]中南大学,长沙410083 [2]北京宇航系统工程研究所,北京100076

出　　处：《焊接学报》2019年第10期142-147,I0007,共7页Transactions of The China Welding Institution

摘　　要：研究了5 mm厚度2195-T8铝锂合金板材摩擦搅拌焊(FSW)接头不同位置的显微组织、腐蚀电化学行为以及在晶间腐蚀介质中的腐蚀特征.结果表明,母材为纤维状晶粒组织,而焊核区为晶粒尺寸小于10μm的完全再结晶组织.2195-T8铝锂合金母材时效强化相为T1相(Al2CuLi)和θ'相(Al2Cu),热力影响区大部分T1相和全部θ'相已重新溶解至基体中,而焊核区所有T1相和θ'相均重新溶解.从母材至焊核区,电位逐渐增加,相应地FSW接头上表面发生宏观平面电偶腐蚀,焊核区承担阴极电流,而母材部分则承担阳极电流.在晶间腐蚀介质中,焊核区表面发生程度较轻的均匀腐蚀,母材部分发生深入基体内部的腐蚀.Microstructures,electrochemical behavior and corrosion feature of different locations in 2195-T8 Al-Li alloy FSW joint were investigated.The parent metal possesses fiber-like grains,but the nugget zone is featured with fully recrystallized grains with size less than 10μm.The strengthening precipitates of the parent metal are T1(Al2CuLi)andθ'(Al2Cu).In the thermo-mechanically affected zone,most T1 and allθ'are re-dissolved,but all T1 andθ'are re-dissolved in the nugget zone.From the parent metal to the nugget zone,the potential increases.Accordingly,galvanic corrosion occurs on the FSW joint surface,the parent metal undertakes anodic current and the nugget zone undertakes cathodic current.In the intergranular corrosion medium,superficial corrosion occurs on the nugget zone surface,but corrosion penetrates inside the parent metal.

关 键 词：铝锂合金 摩擦搅拌焊 显微组织 腐蚀 电化学行为 

分 类 号：TG453.9[金属学及工艺—焊接]