【摘要】 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。更多还原

【Abstract】 The diffusion welding behavior of single crystalline Cu to single crystalline α Al 2O 3 with a Nb film interlayer and the joint microstructure properties were studied by TEM, SEM/EDS analyses and four point bend testing. The Nb film interlayer deposited by electron beam evaporation on the ceramic side prior to diffusion welding was found to be polycrystalline and fiber textured after diffusion bonding, with the close packed plane (110) being parallel to the (0001) basal plane of α Al 2O 3. The fracture energy of Cu/α Al 2O 3 diffusion welded joints was greatly increased by the introduction of the thin film Nb interlayer whereas diffusion welding can be performed at a relatively low temperature (900°C). The increase in fracture energy of the joints with Nb film interlayer was attributed to the strong adhesion of Nb to α Al 2O 3 combined with larger plastic deformation in the metal side during fracture. TEM observations showed large amounts of dislocations existing at the interfacial regions.更多还原