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应用电场激活扩散连接技术(FADB)实现AZ31B与Al的连接。研究了电场对AZ31B/Al结合界面扩散反应和扩散溶解层结构的影响。采用光学显微镜、扫描电子显微镜、X射线能谱与X射线衍射仪等方法分析了扩散溶解层的显微组织、相组成和元素分布。结果表明,在FADB条件下以铝粉为中间层时扩散溶解层由均匀共晶层、过渡层和胞状晶组成;以铝箔为中间层时由镁合金侧共晶层和铝侧过渡层构成。电场强度对扩散溶解层宽度和形态均有显著影响。溶解层随电流密度升高而变宽。以铝粉为中间层在温度450℃,时间50min,电流密度80A·cm-2时过渡层宽度为120μm,为未施加电场时的12倍。电流对共晶层内晶粒尺寸有显著影响。当电流密度由28A·cm-2升至48A·cm-2时,点状晶粒晶粒尺寸由2μm降至0.5μm。
Application of electric field activated diffusion bonding (FADB) to achieve AZ31B and Al connections. The effect of electric field on the diffusion reaction and the structure of the diffusion-dissolution layer at AZ31B / Al interface was investigated. The microstructure, phase composition and elemental distribution of the diffusion-dissolved layer were analyzed by optical microscope, scanning electron microscopy, X-ray diffraction and X-ray diffraction. The results show that the diffusion-dissolution layer consists of homogeneous eutectic layer, transition layer and cellular crystal under the condition of FADB aluminum powder. When aluminum foil is used as the intermediate layer, the diffusion layer consists of magnesium alloy side eutectic layer and aluminum side transition layer. The electric field intensity has a significant effect on the width and morphology of diffusion solution. The dissolution layer broadens as the current density increases. With aluminum powder as the intermediate layer at a temperature of 450 ℃, time 50min, the current density of 80A · cm-2 when the transition layer width of 120μm, 12 times when no electric field. The current has a significant effect on the grain size in the eutectic layer. When the current density increased from 28A · cm-2 to 48A · cm-2, the grain size of the dot grains decreased from 2μm to 0.5μm.