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采用真空扩散焊技术获得了镁合金(MB2)和铝合金(2A12)的焊接接头。采用无损检测、显微硬度、X射线衍射、扫描电镜及电子探针等测试方法,主要研究了保温时间对MB2/2A12扩散焊接头形成的影响,并分析合金中微量元素的存在对接头的作用。结果表明,保温时间较短时,原子扩散不充分,随着保温时间的延长,原子相互间达到充分扩散,焊接界面结合紧密,但过长的保温时间会导致高硬度金属间化合物的生长,对接头产生不利的影响。合金中微量元素在接头处形成富集,并阻碍镁-铝间的相互扩散,且在富集区域产生纵向裂纹,影响焊接接头的强度。
The welding joints of magnesium alloy (MB2) and aluminum alloy (2A12) were obtained by vacuum diffusion welding. The influence of holding time on the formation of MB2 / 2A12 diffusion welded joints was studied by using non-destructive testing, microhardness, X-ray diffraction, scanning electron microscopy and electron probe. The effects of the presence of trace elements on the joints . The results show that when the holding time is short, the atom diffusion is not sufficient. As the holding time prolongs, the atoms are fully diffused and the bonding interface is close together. However, the long holding time leads to the growth of high hardness intermetallic compounds. Joints have adverse effects. The trace elements in the alloy are enriched in the joints and hinder the mutual diffusion between magnesium and aluminum, and produce longitudinal cracks in the enrichment zone, which will affect the strength of welded joints.