摘要
采用无匙孔搅拌摩擦点焊和真空扩散焊对AZ31B镁合金和DP600镀锌钢板进行搭接点焊试验,利用扫描电镜、能谱仪及拉伸试验对无匙孔搅拌摩擦点焊接头与真空扩散焊接头进行微观组织及力学性能的对比分析.结果表明,镁钢无匙孔搅拌摩擦点焊接头结合方式为机械结合与冶金结合共同作用,冶金结合表现为:镁钢界面发生扩散生成由Mg,Fe,O形成的金属间化合物,镁合金中的合金元素与铁生成金属间化合物,机械结合表现为:钢像"钉子"一样插入到镁合金基体中,且在镁钢结合界面处,两种金属呈锯齿状咬合,接头抗剪切载荷平均可达10.36k N,而只存在单纯扩散结合方式的真空扩散焊接头抗剪切载荷平均仅为2.5 k N.通过两种接头对比分析可知,机械结合对接头力学性能的贡献远远大于冶金结合,其接头结合方式以机械结合为主.
The lap welding of AZ31 B Mg alloy to DP600 galvanized steel were successfully achieved by friction stir spot welding( FSSW) and vacuum diffusion welding. Scanning electron microscopy,energy disperse spectroscopy and tensile tests were used to investigate the microstructures and mechanical properties of the welded joints at the best welding parameters. The results show that there is no keyhole found in the FSSW joint and the good weld appearance is obtained. The bonding mechanism of the joints are mechanical bonding and metallurgical bonding.Intermetallic compounds of Mg,Fe and O formed because of the diffusion at the interface of magnesium and steel during the metallurgical bonding process. In the mechanical bonding process,some of the steel insert into the magnesium alloy substrate like nails and there exists serrated combination morphology at the interface between Mg and steel,the others is mixed into the magnesium alloy under the stir effect of stir pin which greatly improved the mechanical properties of joint of magnesium alloy to steel. For both the kinds of bonding mechanism,about 75. 9%of the mechanical properties is contributed by mechanical bonding and mechanical bonding is the main bonding mechanism in the FSSW process.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2016年第8期17-20,129-130,共4页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目(51265030)
关键词
搅拌摩擦点焊
镁合金
镀锌钢
力学性能
结合方式
friction stir spot welding
AZ31B magnesium alloy
DP600 galvanized steel
mechanical properties
bonding mechanism
