TiZrNiCu钎焊Si3N4-MoSi2复合陶瓷与Nb接头组织与力学性能

Microstructure and Mechanical Properties of Si3N4-MoSi2 composite Ceramic and Nb Joints Brazed with TiZrNiCu

摘要:

采用高温活性钎料TiZrNiCu对Si₃N₄-MoSi₂复合陶瓷和金属Nb进行真空钎焊试验,研究了其典型界面组织组成及形成机理,分析了钎焊温度和保温时间对钎焊接头界面组织及力学性能的影响规律。结果表明,接头典型界面结构为Nb/β-Ti/(Ti. Zr)₂(Cu, Ni)+β-Ti+(Ti, Zr)₅Si₃/TiN+(Ti, Zr)₅Si₃+MoSi₂/Si₃N₄-MoSi₂。钎焊温度和保温时间主要通过控制Si₃N₄-MoSi₂复合陶瓷母材中Si原子向钎料中扩散程度,来影响钎缝中(Ti, Zr)₅Si₃化合物的数量及分布,进而影响钎焊接头的抗剪强度。在920 ℃/10 min的工艺参数下,Si₃N₄-MoSi₂/Nb接头的室温抗剪强度最高达到112 MPa,选择最优参数条件下的Nb/Si₃N₄-MoSi₂钎焊接头在500 ℃和600 ℃条件下进行高温剪切实验,其高温抗剪强度分别达到123 MPa和131 MPa。

Abstract:

The vacuum brazing experiment of Si₃N₄-MoSi₂ composite ceramic and Nb was successfully carried out with high-temperature active brazing filler TiZrNiCu. The typical interface structure and formation mechanism of the brazing joint were studied, and the effects of brazing temperature and holding time on interface structure and mechanical properties of brazed joints were analyzed. The results show that the typical interface structure of the joint was Nb/β-Ti/(Ti, Zr)₂(Cu, Ni)+β-Ti+(Ti, Zr)₅Si₃/TiN+(Ti, Zr)₅Si₃+MoSi₂/Si₃N₄-MoSi₂. Brazing temperature and holding time affected the amount and distribution of (Ti, Zr)₅si₃ compound in the brazing seam by controlling the diffusion degree of Si atoms in Si₃N₄-MoSi₂ composite ceramic to the brazing filler, thus affecting the shear strength of the brazed joint. The highest room temperature shear strength of Nb/Si₃N₄-MoSi₂ joint was 112 MPa at 920 ℃/10 min. The high-temperature shear strength of Nb/Si₃N₄-MoSi₂ brazed joint was 123 MPa and 131 MPa at 500 ℃ and 600 ℃, respectively.