稀土钼合金电子束焊接接头组织研究

Research on Microstructure of Electron Beam Welded Joints of Rare Earth-Molybdenum Alloy

摘要: 用真空电子束焊机对1 mm厚的稀土钼镧合金板进行电子束焊接，通过焊接工艺参数的对比以及接头组织和焊缝缺陷的检测分析，本文研究了稀土钼合金电子束焊接接头的微观组织及其影响因素。结果表明：钼镧合金电子束焊接过程中，稀土元素La以La2O3形式存在且并未发生明显损耗；束流的增加、焊速的降低以及扫描幅值的增大有利于平整美观焊缝表面的形成；钼镧合金电子束焊接接头为柱状晶组织，存在着气孔缺陷和裂纹缺陷，焊缝区及热影响区硬度均高于母材区。

Abstract: The rare earth molybdenum-lanthanum alloy sheets with thickness of 1 mm were welded using vacuum electron beam welder. By comparison of welding processing parameters and detection and analysis of welded joint microstructure and weld defects, the microstructure of electron beam welded joints and influencing factors of rare earth-molybdenum alloy were studied. The results show that, the existing form of rare earth La element is La2O3 and it doesn’t loss during the process of electron beam welding for molybdenum-lanthanum alloy. It is helpful for getting the smooth and fine weld surface by increasing of electron beam current, reducing of welding speed and increasing of scanning amplitude. The molybdenum-lanthanum alloy electron beam welded joints were columnar grain structure, and there were porosity defect and crack defect. The hardness of weld zone and heat affected zone were higher than that of base metal.