摘要
针对6082铝合金脉冲MIG焊接过程中存在气孔、接头软化等瓶颈问题,提出机械振动辅助焊接的方法,采用高速摄像、扫描电镜(SEM)、透射电镜(TEM)和力学性能测试等方法研究机械振动对电弧形态、熔滴过渡行为、焊缝气孔分布、接头沉淀相演变及力学性能的影响。结果表明,在焊接过程中施加机械振动,电弧不易发生飘移,熔滴过渡稳定,焊缝气孔数量减少。机械振动可以有效细化焊缝晶粒,促进焊缝中形成GP区,使热影响区中粗大的Mg2Si沉淀相粒子尺寸减小,细小的α-Al Fe Mn Si沉淀相粒子数量增多,分布更加弥散,产生明显的沉淀硬化效果,提高接头强度和硬度。当振动频率为100 Hz时,接头的抗拉强度最高,达到246 MPa,与不施加振动的接头强度相比提高了约12%。过大的机械振动频率会导致焊缝成形变差,恶化接头的力学性能。研究成果对于提高新能源汽车车身的铝合金空间框架结构的服役安全性和使用寿命具有重要意义。
Aiming at the critical technical issues such as porosity and joint softening in the pulsed MIG welding process of 6082 aluminum alloy,a mechanical vibration-assisted welding method was proposed.The high-speed camera,scanning electron microscopy(SEM),transmission electron microscopy(TEM),and testing of mechanical properties are used to study the effect of mechanical vibration on the arc morphology,droplet transfer behaviour,porosity distribution,precipitate evolution,and mechanical properties.The results show that when mechanical vibration is applied during welding,the arc is less likely to drift,the droplet transfer is stable,and the number of weld pores is reduced.Mechanical vibration can effectively refine the grains and promote the formation of GP zones in the weld,reduce the size of coarse Mg2Si particles but increase the number of fineα-AlFeMnSi particles in the heat affected zone,and make the distribution of precipitates more dispersed,resulting in obvious precipitation-hardening effect and thus improving the strength and hardness of the joint.At a vibration frequency of 100 Hz,the joint has the maximum tensile strength of 246 MPa,an increase of approximately 12%compared to the joint obtained without mechanical vibration.Excessive vibrational frequency can lead to a poor appearance of weld,thus deteriorating the mechanical properties of the joint.The results are of important significance in increasing the service safety and life of the bodies of electric cars.
作者
石铭霄
陈九公
李敬勇
茅卫东
李盛良
马相
SHI Mingxiao;CHEN Jiugong;LI Jingyong;MAO Weidong;LI Shengliang;MA Xiang(School of Materials Science and Engineering,Jiangsu University of Science and Technology,Zhenjiang 212003;Chery New Energy Automobile Co.,Ltd.,Wuhu 241003;Anhui Key Laboratory of New Energy Automobile Lightweight Technology,Wuhu 241003;SINTEF Industry,Oslo 0314,Norway)
出处
《机械工程学报》
北大核心
2025年第8期138-147,共10页
Journal of Mechanical Engineering
基金
安徽省科技重大专项(2019b05050006)
江苏省高等学校基础科学(自然科学)研究重大(22KJA460011)
江苏省研究生科研与实践创新计划(SJCX21_1771)资助项目。
