镍中间层对铝/镁异种金属搅拌摩擦焊接头微观组织的影响  

Effect of Ni interlayer on microstructure of aluminum/magnesium dissimilar metal friction stir welding joint

作　　者：董少康 马宇航 朱浩[1,2] 王晨霁 曹志龙 王军 DONG Shaokang;MA Yuhang;ZHU Hao;WANG Chenji;CAO Zhilong;WANG Jun(Shijiazhuang Tiedao University,Shijiazhuang,050043,China;Hebei Key Laboratory of New Materials for Collaborative Development of Traffic Engineering and Environment,Shijiazhuang,050043,China;Hebei University of Science and Technology,Shijiazhuang,050018,China)

机构地区：[1]石家庄铁道大学,石家庄050043 [2]河北省交通工程与环境协同发展新材料重点实验室,石家庄050043 [3]河北科技大学,石家庄050018

出　　处：《焊接学报》2022年第12期84-89,I0008,共7页Transactions of The China Welding Institution

基　　金：河北教育厅重点项目(ZD2019102)。

摘　　要：采用搅拌摩擦焊(friction stir welding,FSW),引入厚度为0.05 mm镍箔作为中间层,在焊接速度不变条件下,采用不同转速对厚度为4 mm的6061铝合金和AZ31镁合金进行平板对接,对接头进行系列微观组织表征及力学性能测试,探讨转速对接头中镍颗粒分布状态,金属间化合物(intermetallic compounds,IMCs)种类与分布及接头强度的影响规律.研究结果表明:与未引入中间层接头相比,引入镍改变了铝/镁异种金属FSW接头焊核区(weld nugget zone,WNZ)中IMCs种类及分布,WNZ存在明显的镁合金与铝合金相间的带状组织,其上分布着絮状Al_(12)Mg_(17)、颗粒状Mg_(2)Ni、层状Al_(3)Mg_(2)及大小不一的镍箔颗粒;随着转速增加,镍箔颗粒分布愈加均匀,Al_(3)Mg_(2)数量相对减少,且脆性Al_(3)Mg_(2)由连续分布逐渐演变为断续分布;当转速为750 r/min时,接头抗拉强度达到最大值,与未引入中间层接头相比,引入镍中间层接头抗拉强度提高了56 MPa,达到镁合金的56.9%.The flat butt welding tests were carried out on 6061 aluminum alloy and AZ31 magnesium alloy with the thickness of 4 mm by introducing 0.05 mm Ni foil interlayer under the condition of constant travel speed and different rotation speeds using the friction stir welding(FSW)technology.The effects of rotation speeds on the distribution of Ni foil particles,the types and distribution of the intermetallic compounds(IMCs)and the strength of the joints were investigated by series of microstructure characterization and mechanical property tests.The results showed that compared to the joint without Ni,the introduction of Ni foil interlayer changed the types and distribution of IMCs in the weld nugget zone(WNZ).In WNZ,there was an obvious banded structure between magnesium alloy and aluminum alloy on which the flocculent Al_(12)Mg_(17),granular Mg_(2)Ni,lamellar Al_(3)Mg_(2),and Ni foil particles of varying sizes were distributed.With the increasing of rotation speed,the distribution of Ni became more uniform,while the Al_(3)Mg_(2) decreased relatively,and the distribution of the brittle Al_(3)Mg_(2) gradually changed from continuous to intermittent.The tensile strength of the joint reached the maximum value when the rotation speed was 750 r/min.Compared to the joint without Ni,the tensile strength of the joint with the introduction of Ni foil interlayer was increased by 56 MPa,which was 56.9%of the strength of magnesium alloy.

关 键 词：铝/镁异种金属 搅拌摩擦焊 镍箔中间层 金属间化合物 

分 类 号：TG457.14[金属学及工艺—焊接]