【摘要】 采用韧性好、呈疏松多孔结构的三维SiO₂纤维编织复合材料(3D-SiO_2f)作为中间层，以AgCuTi+Ti作为钎料，在加热温度为970℃,保温时间20 min的条件下，在真空钎焊炉中对SiO_2f/SiO₂复合材料和金属Nb进行连接，形成高质量接头.在钎焊加热时，钎料中的活性元素Ti与3D-SiO_2f中间层中大量的SiO₂短纤维发生冶金反应，从而使钎焊接头中反应生成大量TiSi₂和Ti₂Cu颗粒相，以及未反应完的SiO₂短纤维，且弥散分布，这些弥散分布的颗粒相能够有效降低SiO_2f/SiO₂复合材料与活性钎料或金属Nb的热膨胀系数不匹配度，使焊缝中的热膨胀系数得到梯度过渡，改善钎焊接头中的残余应力，接头强度提高到65 MPa左右.此外，E-SiO_2f/SiO₂-Nb@3D-SiO_2f接头残余应力分布的模拟结果再一次证实引入3D-SiO_2f中间层能够有效缓解接头残余应力.更多还原

【Abstract】 3D-SiO_2f, a three-dimensional SiO₂ fiber woven composite with good toughness and loose porous structure, was used as the interlayer, and AgCuTi+Ti was used as the brazing material to join the SiO_2f/SiO₂ composite and metal Nb in a vacuum brazing furnace at a heating temperature of 970 ℃ and a holding time of 20 minutes to form a high-quality joint. SiO_2f interlayer is a loose, porous structured and ductile material. When brazing is heated, the active element Ti in the brazing material reacts metallurgically with a large number of SiO₂ short fibers in the 3D-SiO_2f interlayer, resulting in a large number of TiSi₂ and Ti₂Cu particle phases and unreacted SiO₂ short fibers in the brazed joint, which are diffusely distributed. The particle phase can effectively reduce the mismatch of thermal expansion coefficient between SiO_2f/SiO₂ composites and active brazing material or metal Nb, so that the thermal expansion coefficient in the brazed joints can get gradient transition and improve the residual stresses in the brazed joints, and the joint strength is increased to about 65 MPa. In addition, the simulation results of residual stress distribution in E-SiO_2f/SiO₂-Nb@3D-SiO_2f joints once again confirm the conclusion that the introduction of 3D-SiO_2f interlayer can effectively relieve the residual stresses in the joints.更多还原