中文摘要：

针对铝/钢电弧辅助激光对接焊,根据流体力学基本原理,采用VOF（Volume of Fluid）方法追踪自由表面,建立焊接熔池的三维数学模型.通过加载激光热源和电弧辅助激光热源,运用FLOW-3D软件求解得到不同热源作用下熔池的温度场、自由表面及界面接触角.结果表明：单激光作用下x轴方向上距激光热源15mm处的金属温度约为500K,熔池温度场分布范围小,液态金属的润湿铺展受限;辅助电弧的引入改善了温度场分布,为液态金属在钢表面的铺展提供较长时间,x轴方向上距激光热源15mm处的金属被电弧再次加热形成面积较大的熔池,促进了液态金属的润湿铺展;与单激光作用相比,当焊接时间t=6s时,在x=45mm处,电弧辅助激光作用下熔池yz面的自由表面变形较大,铝/钢焊接界面接触角较小,液态金属在钢表面的润湿铺展效果较好.

英文摘要：

Aimed at the aluminum/steel arc-assisted laser butt welding, the free surface was tracked ac- cording to basic principles of fluid mechanics and by using VOF（volume of fluid） method and a three di- mensional mathematical model of welding pool was established. By loading laser heat source and arc-assis- ted laser heat source, FLOW-3D software was used to obtain the temperature field, and free surface of the molten pool and the contact angle under different heat source action. The result showed that the tempera- ture of metal at the point of 15 mm away from laser heat source on x-axis would be about 500 K under the action of single laser, the region of molten pool temperature field would be smaller, so that liquid metal wetting and spreading was restricted. The introduction of assistant arc would improve the temperature field, provide a longer time for wetting and spreading of liquid metal on the steel surface, the metal away from the laser heat source by 15 mm on z-axis would be reheated by the arc and form a larger molten pool, so that the wetting and spreading of liquid metal was promoted. Compared with single laser＇s effect, when welding time t~6 s and at x=45 mm, the molten pool＇s free surface deformation on yz-plane was larger and the aluminum/steel welding interface contact angle was small under the action of assisted arc, so that the result of liquid metal wetting and spreading on steel surface would be better.