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Co-Nb-Pd-Ni-V钎料真空钎焊Cf/SiC复合材料的接头组织与性能

Microstructure and strength of the Cf/SiC composite joint brazed with Co-Nb-Pd-Ni-V filler alloy

  • 摘要: 采用自行设计的Co-Nb-Pd-Ni-V高温活性钎料对碳纤维增强碳化硅(Cf/SiC)复合材料进行钎焊连接,钎焊温度为1 200 ~ 1 320 ℃,钎焊时间固定为10 min. 结果表明,钎料中的V和Nb元素同时发挥反应活性,与Cf/SiC复合材料发生界面反应,在陶瓷界面形成了VC和NbC双层界面反应层. 当钎焊参数为1 280 ℃/10 min,典型的接头组织为(VC/NbC)双界面反应层/(Co,Ni)2Si + CoSi + NbC + Pd2Si/(NbC/VC)双界面反应层. 在此参数下获得的接头性能最佳,其中室温三点弯曲强度为61.0 MPa,在900和1 000 ℃下测得的强度均高于其室温强度,分别为83.2和87.7 MPa. 接头中的NbC和Pd2Si高熔点物相弥散分布在钎缝内部,大大提高了接头的高温性能.

     

    Abstract: The Cf/SiC composite joint was brazed with newly-designed Co-Nb-Pd-Ni-V filler alloy at the brazing temperature from 1 200℃ to 1 320℃, and the brazing time was fixed at 10 min. The results showed that elements V and Nb in filler alloy played active roles in the interfacial reactions during the brazing procedure, and two interfacial reaction layers VC and NbC were formed at the Cf/SiC surface. Under the brazing condition of 1 280℃/-10 min, the joint microstructure can be characterized as (VC/NbC) double layers/(Co, Ni)2Si + CoSi + NbC + Pd2Si/(NbC/VC) double layers. The optimum joint strength can be achieved brazed at 1 280℃ for 10 min, and the room-temperature bend strength was 61.0 MPa. Furthermore, the joint strength tested at 900 and 1 000℃ was even elevated to 83.2 and 87.7 MPa, respectively. The good high-temperature joint strength can be attributed to the formation of high-melting-point compounds, such as NbC and Pd2Si.

     

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