LY12铝合金搅拌摩擦焊接头的残余应力研究  

Study of the Residual Stress in LY12 Aluminum Alloy Friction Stir Welding Joint

作　　者：苏孺 王朋朋 刘晓瑞 王军[1] 王立伟 任锦朝 Su Ru;Wang Pengpeng;Liu Xiaorui;Wang Jun;Wang Liwei;Ren Jinzhao(School of Material Science and Technology,Hebei University of Science and Technology,Shijiazhuang 050018,China;Shijiazhuang Water Conservancy and Hydropower Engineering Department,Shijiazhuang 050031,China)

机构地区：[1]河北科技大学材料科学与工程学院,河北石家庄050018 [2]石家庄市水利水电工程处,河北石家庄050031

出　　处：《稀有金属》2019年第10期1016-1022,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金青年科学基金项目(51701064);国家自然科学基金面上项目(51875168);河北省自然科学基金青年基金项目(E2018208126);国防基础科研计划项目(2017407C002)资助

摘　　要：搅拌摩擦焊(FSW)具有焊接工艺简单、焊接缺陷少等优点,可用于高强度铝合金的焊接。掌握搅拌摩擦焊接头的残余应力演化规律,对优化焊接工艺,延长工件使用寿命具有重要的研究价值和实际意义。本文采用LY12铝合金搅拌摩擦焊接头为研究对象,通过X射线衍射(XRD)对焊接接头进行残余应力测定。X射线衍射峰位置、强度和宽度变化的实验结果表明:主轴转速和焊接速度一定时,热影响区宏观残余应力大于焊缝区域,两个区域的纵向残余应力都大于横向残余应力,纵向应力和横向应力均以压应力为主,纵向残余应力峰值在热影响区为179 MPa。焊接速度一定时,随主轴转速升高,晶格畸变减小,焊缝区压应力先降低后增加,在热影响区不断增加,焊缝区<111>取向表现出先增加后减小趋势;主轴转速一定时,随焊接速度增加,晶格畸变加剧,焊缝区宏观残余应力增加,热影响区残余应力减小,焊缝区<111>取向强度减弱,但仍较<200>取向严重。Friction stir welding(FSW) has the advantages of simple welding process and few defects, and can be used for welding of high strength aluminum alloy. It is of great research value and practical significance to master the law of residual stress evolution of friction stir welding joint for optimizing welding process and prolonging service life of workpiece. The LY12 aluminum alloy friction stir welding joints were used as the research object. The residual stress of the welded joint was measured by X-ray diffraction(XRD). The 2 theta angle, intensity and broadening of diffraction peak showed that when the spindle speed and welding speed were constant, the residual stress was greater in the heat affected zone than that in the weld zone, the residual stress parallel to the longitudinal direction was larger than that in transverse direction in both regions, and the residual stress was dominated by compressive stress in both direction, indicating that mechanical stirring was dominant. When the welding speed was constant, with the increase of the spindle speed, the lattice distortion decreased, the compressive residual stress decreased and then increased in the weld zone, and in the heat affected welding speed, the heat input decreased, the lattice distortion intensified, the macroscopic residual stress increased in the weld zone, the residual stress decreased in the heat affected zone. When the spindle speed was 600 r·min-1, the orientation of <111> decreased, but it was still more serious than <200> orientation.

关 键 词：LY12铝合金 搅拌摩擦焊 X射线衍射 残余应力 晶格畸变 

分 类 号：TG453.9[金属学及工艺—焊接]