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采用扫描和透射电镜、能谱分析、X射线衍射和 4点弯曲试验研究了Nb膜中间层对单晶Cu与单晶α -Al2 O3 的扩散焊接特性以及接头组织和性能的影响。结果表明 ,通过电子束蒸镀获得的多晶Nb膜中间层扩散焊后具有织构组织 ,其密排面 (110 )平行于Al2 O3 的 (0 0 0 1)基面。Nb膜中间层的加入显著提高了Cu/Al2 O3 扩散焊接头的断裂能量 ,而扩散焊接温度可以与无Nb膜中间层时保持不变。带Nb膜中间层的Cu/Al2 O3接头所具有的高断裂能量是由于Nb与Al2 O3 较强的键合以及断裂时金属侧较大的塑性变形功二者综合作用的结果。透射电镜观察表明 ,在Cu/Al2 O3 扩散焊接头的界面附近存在大量位错。
The effects of Nb interlayer on the diffusion bonding characteristics and the microstructure and properties of single-crystal Cu and single-crystal α -Al 2 O 3 were investigated by scanning and transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction and 4-point bending test. The results show that the polycrystalline Nb film intermediate layer obtained by electron beam evaporation has a textured structure after diffusion welding, and its close-packed surface (110) is parallel to the (0 0 0 1) base surface of Al 2 O 3. The addition of Nb intermediate layer significantly improves the fracture energy of the Cu / Al 2 O 3 diffusion bonding joint, while the diffusion bonding temperature can be kept unchanged with the Nb-free intermediate layer. The high fracture energy of the Cu / Al 2 O 3 joint with the Nb film interlayer is due to the combined effect of the stronger bond between Nb and Al 2 O 3 and the greater plastic deformation work on the metal side during fracture. Transmission electron microscopy showed that there was a large number of dislocations near the interface of Cu / Al 2 O 3 diffusion welding joint.