激光焊接7A52高强度铝合金焊缝气孔形成机理研究  

Mechanism of Pore Formation in Laser Welding of 7A52 High-Strength Aluminum Alloy Welds

作　　者：苏菠 陈大江 张大斌[2] 胡江 张淑清[1] 简汉青 SU Bo;CHEN Dajiang;ZHANG Dabin;HU Jiang;ZHANG Shuqing;JIAN Hanqing(School of Traffic Management Engineering,Guangxi Police College,Nanning 530028,Guangxi,China;School of Mechanical Engineering,Guizhou University,Guiyang 550025,Guizhou,China)

机构地区：[1]广西警察学院交通管理工程学院,广西南宁530028 [2]贵州大学机械工程学院,贵州贵阳550025

出　　处：《重庆交通大学学报（自然科学版）》2024年第3期128-134,共7页Journal of Chongqing Jiaotong University(Natural Science)

基　　金：2023年度广西高校中青年教师科研基础能力提升项目(2023KY0913);广西公安厅项目(2023GAQN102)。

摘　　要：为实现航空航天装备和汽车的结构轻量化,故使用厚度连续变化的7A52高强度铝合金板代替传统不锈钢等金属,从结构和材料密度两个角度实现轻量化。通过恒定功率的激光焊接铝合金变厚板时,单位体积内吸收的热量不同,匙孔演变产生气孔,影响焊缝质量。焊缝内气孔主要由金属蒸气作用到匙孔壁,匙孔壁受力不均产生,为探究匙孔动态演变产生气孔的机理,提出将匙孔壁面的局部范围空间分为一定数量的小正方体块,计算相对较小范围内的能量和力,计算结果结合焊缝微观检测结果,分析力对匙孔壁面的作用。厚度小的一端焊缝充分熔透,匙孔壁面受到金属蒸气产生的压力和表面张力的不平衡作用,匙孔壁面局部范围形成气泡,厚度大的一端未熔透。铝合金焊缝凝固后,晶粒生长影响气泡的逃逸路径,气泡最后演变为气孔。In order to realize the lightweight structure of aerospace equipment and automobile,7A52 high-strength aluminum alloy plate with continuously varying thickness was therefore used to replace traditional stainless steel and other metals,achieving lightweight from the perspective of structure and material density.When welding aluminum alloy thickened plates with a constant power laser,the amount of heat absorbed per unit volume varied and the keyholes evolved to pores,which affected the quality of the weld seam.The pores in the weld seam were mainly caused by the action of metal vapor on the keyhole wall and the uneven force on the keyhole wall.In order to explore the pore formation mechanism caused by dynamic evolution of the keyhole,the local space of the keyhole wall was divided into a certain number of small cubes,and the energy and forces in a relatively small range were calculated.The effect of force on the keyhole wall surface was analyzed by combining the calculation results with the microscopic inspection results of the weld seam.The weld seam at the thinner end was fully melted,the keyhole wall was subjected to an unbalanced effect of pressure and surface tension generated by metal vapor,resulting in the formation of bubbles in a local area of the keyhole wall,and the thicker end is not fully melted.After the solidification of aluminum alloy weld,the grain growth affected the escape path of the bubbles,and the bubbles eventually evolved into pores.

关 键 词：机电工程 激光焊接 焊缝 铝合金 匙孔 

分 类 号：TH16[机械工程—机械制造及自动化]