摘要
对1.4 mm厚DP590双相钢和1.2 mm厚6016铝合金平板试件进行有无胶层加入的激光搭接焊试验,利用卧式金相显微镜、扫描电镜(SEM)、背散射电子衍射技术(EBSD)、能谱仪(EDS)、显微硬度分析仪和微机控制电子万能试验机等研究有无胶层辅助激光焊接头焊缝区域的金相组织、断口形貌、相分布及含量、晶粒大小、界面元素分布、显微硬度与接头力学性能。结果表明:在激光功率为1800 W、焊接速度为40 mm/s、离焦量为+2 mm、采用Ar为保护气体且流量为15 L/min的条件下,添加胶层时,焊接试样焊缝表面成形性良好,焊缝区无软化组织生成,焊接接头的平均剪切强度为41.33 MPa;与没有添加胶层的相比,试样的剪切强度提高1.44倍。添加胶层可增加焊缝熔深和熔宽,有利于钢/铝的焊合,钢/铝界面生成具有延性富Fe的Fe-Al化合物,均匀分布的晶粒有助于试件承受的外力均匀分布在焊接接头的搭接区域,因而添加胶层对焊接接头的力学性能有改善作用。
The fiber laser welding test with or without adhesive layer addition was carried out on the DP590 dual phase steel with thickness of 1.4mm and 6016 aluminum alloy with thickness of 1.2 mm. By horizontal metallographic microscopy, scanning electron microscopy, electron backscatter diffractometry, energy dispersive spectroscopy, the micro-hardness tester and microcomputer control electronic universal testing machine, the microstructure of the welded joint region, fracture morphology, distribution and content of phase, grain size, the distribution of interface elements and mechanical properties of welded joints were studied. The results show that the morphology of welding surface can be improved and softening microstruc^re of the weld zone does not form when the welding power is 1800 W, welding speed is 40 mm/s, the defocus distance is ＋2 mm, and Ar gas acts as the protection gas with flow rate of 15 L/min. The average shear strength of the welding sample with adhesive layer addition reaches 41.33 MPa. Compared with that without adhesive layer addition, the average shear strength of weld joint increases by 1.44 times. The increases of weld penetration and width by adding adhesive layer promote the combination of the steel and aluminum interface, Fe-rich Fe-A1 intermetallic compounds has better ductility, the uniform size grains distribute in the region of the welded joint, which can improve the mechanical properties of welded joints with adhesive layer addition.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2015年第9期2381-2388,共8页
The Chinese Journal of Nonferrous Metals
基金
国家高技术研究发展计划重点项目(2012AA111802)
湖南大学汽车车身国家重点实验室自主课题(71075003)
关键词
激光焊接
钢/铝异种金属
胶层
显微组织
力学性能
laser welding
steel/aluminum dissimilar metal
adhesive layer
microstructure
mechanical property
