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对1.4 mm厚的DP590双相钢和1.2 mm厚的6016铝合金平板试件进行添加Sn-5%Zr(质量分数,下同)粉末的激光搭接焊试验,利用卧式金相显微镜、扫描电镜(SEM)、X射线衍射仪(XRD)、背散射电子衍射技术(EBSD)和微机控制的电子万能试验机等研究了添加Sn-5%Zr粉末对焊缝微观形貌、焊接区域金相组织、断口形貌、主要物相、相的分布及含量、晶粒大小与接头力学性能的影响,采用基于密度泛函理论的第一性原理方法,计算了添加Sn-5%Zr粉末后新形成物相Fe Sn、Fe3Sn和Fe3Al、Fe Al、Fe2Al5等Fe-Al金属间化合物的模量。结果表明,添加Sn-5%Zr粉末钢/铝接头平均剪切强度为37.90 MPa,与未添加粉末相比,剪切强度提高,新形成Zr Al3化合物细化了钢/铝界面Fe-Al金属间化合物的晶粒尺寸,Sn抑制Al向焊缝熔池内扩散,减少Fe-Al金属间化合物层厚度,新形成物相Fe Sn,Fe3Sn具有较好的延性,Sn-5%Zr粉末改变了界面层Fe-Al金属间化合物脆性相与延性相的比例,添加粉末增加焊缝熔宽,提高焊合率,因而添加Sn-5%Zr粉末改善了焊接接头的力学性能。
The laser lap welding test of 1.4 mm thick DP590 dual-phase steel and 1.2 mm thick 6016 aluminum alloy flat plate was carried out with the addition of Sn-5% Zr (mass fraction) SEM, XRD, EBSD and computer-controlled electronic universal testing machine were used to study the effects of adding Sn-5% Zr powder on the microstructure, The morphology, microstructure, fracture morphology, major phase, distribution and content of phase, grain size and mechanical properties of the joint were investigated. The first principles method based on density functional theory The formation of the phase Fe Sn, Fe3Sn and Fe3Al, Fe Al, Fe2Al5 and other Fe-Al intermetallic compounds modulus. The results show that the average shear strength of the steel / aluminum joint with Sn-5% Zr powder is 37.90 MPa, the shear strength increases compared with the un-added powder, the newly formed ZrAl3 compound refine the Fe-Al metal The Sn-5% Zr powder changed the interface between the new compound phase Fe Sn and Fe3Sn, and the Sn-5% Zr powder changed the interfacial grain size. Sn inhibited the diffusion of Al into the weld pool and reduced the thickness of the Fe-Al intermetallic compound layer Fe-Al intermetallic compound of brittle phase and ductile phase ratio, add the powder to increase weldment broadening and improve the welding rate, thus adding Sn-5% Zr powder to improve the mechanical properties of welded joints.