2A14厚板铝合金SSFSW角焊缝接头组织及性能  

Microstructure and Mechanical Property of Fillet Welded Joint by Stationary Shoulder Friction Stir Welding for 2A14 Aluminum Alloy Thick-plate

作　　者：闫新中 杨新岐[1] 唐文珅 赵慧慧 郭立杰 YAN Xinzhong;YANG Xinqi;TANG Wenshen;ZHAO Huihui;GUO Lijie(School of Materials Science and Engineering,Tianjin University,Tianjin 300354;Shanghai Aerospace Equipment Manufacturer Co.,Ltd.,Shanghai 200245)

机构地区：[1]天津大学材料科学与工程学院,天津300354 [2]上海航天设备制造总厂,上海200245

出　　处：《机械工程学报》2022年第22期186-197,共12页Journal of Mechanical Engineering

基　　金：国防基础科研(JCKY2017203B066);国家自然科学基金(51775371)资助项目。

摘　　要：采用自主研制搅拌针长度为8.5mm的静止轴肩搅拌工具和2A14-T4厚板铝合金进行150°角焊缝接头静止轴肩搅拌摩擦焊工艺试验,探讨焊接工艺参数对接头组织和力学性能的影响规律。结果表明:在500~700r/min主轴转速与40~100 mm/min焊接速度范围内均可获得表面光滑无内部缺陷的角焊缝接头,其外观尺寸可精确控制基本无残余焊接角变形。焊缝区主要由焊核(Stir zone,SZ)组成,SZ形状类似搅拌针圆锥台状或椭圆状、其宽度沿厚度方向分布比较均匀;热力影响区(Thermal mechanical affected zone, TMAZ)及热影响区(Heat affected zone, HAZ)宽度明显较小。焊缝区硬度分布具有明显不均匀特征,最薄弱区位于TMAZ与HAZ的交界处。主轴转速变化对焊缝区平均硬度影响较小,但随着焊接速度增加其平均硬度明显增大。角焊缝前进侧等效拉伸强度大于后退侧,等效拉伸强度随转速增加而减小,焊速的增大而增大。在500 r/min-100 mm/min焊接工艺下所得到的接头等效拉伸强度最高,可达到母材的79.24%。在拉-剪复合承载模式下,角焊缝拉伸试样宏观塑性变形很小呈现脆性断裂特征。The welding experiments of fillet welded joints with 150-degree are performed for 2A14-T4 aluminum alloy thick plate by using the self-developed stationary shoulder friction stir welding(SSFSW) tools with the pin of 8.5mm length, and the influences of welding parameters on the microstructures and mechanical properties of fillet welded joints are explored and discussed. It is shown that the defect-free fillet welded joints with smooth weld surface can be produced in the range of 500-700 r/min rotational speeds and 40 mm/min-100 mm/min welding travel speeds, the shape and size of fillet joints can be controlled accurately and almost no any residual welding angular deformation is produced. The weld zone is mainly composed of stir zone(SZ), the shape of SZ is similar to the cone of stirring pin or elliptical shape, and its width is evenly distributed across the thickness of the plate;the widths of the thermal-mechanical affected zone(TMAZ) and heat affected zone(HAZ) are obviously smaller. The microhardness distribution is apparently uneven in the weld zone, and the weakest site is located at the interface between TMAZ and HAZ. The rotational speed has little effect on the average microhardness of the weld zone, but with the increase of welding speed, the average hardness increases obviously. The equivalent tensile strength(ETS) of the advancing side(AS) of the fillet welded joint is higher than that of the retreating side(RS). The ETS decreases with the increase of rotational speed but increases with the increase of welding speed. The ETS obtained at the welding process of 500 r/min-100 mm/min has the highest value, reaching 79.24% of the base material. The tensile specimens in the tension-shear loading modes have minor macro-plastic deformation and present the feature of the brittle fracture process.

关 键 词：2A14铝合金 角焊缝接头 静止轴肩搅拌摩擦焊 组织特征 力学性能 

分 类 号：TG453[金属学及工艺—焊接]