压铸镁合金激光焊气孔形成原因的实验研究

压铸镁合金因含气量高而使得激光焊接气孔问题非常突出,为实现压铸镁合金的低气孔率焊接技术,通过对母材固态加热前后气孔特征参数、密度变化的分析以及焊前除氢后施焊与不除氢施焊气孔倾向的比较,研究了压铸镁合金中气体来源的特点及气孔形成过程.结果表明,母材中同时含有分子氢和原子氢,以高压气孔形式存在的分子氢以及以过饱和固溶形式存在的原子氢均是导致压铸镁合金激光焊产生大量气孔的原因.而向焊缝中引入Zr元素可以显著降低气孔倾向,但Zr的作用机理还有待于深入研究.

EXPERIMENTAL STUDY ON THE REASON OF PORE FORMATION IN LASER WELDING OF DIE-CAST MAGNESIUM ALLOY

Because of their low density,high strength-to-weight ratio and high damping capacity, magnesium alloys have gained increasing applications in many fields,especially for die-cast magnesium alloys.The application of die-cast magnesium alloys in structures and repair welding of casting defects necessitates the development of welding techniques.As a high energy density thermal source,laser welding can reduce many welding defects compared with conventional welding methods, but pore formation during welding of di...