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填充泡沫Ti/AlSiMg的SiC陶瓷钎焊接头的组织与性能

Microstructure and property of SiC ceramic brazed joint filled with Ti foam/AlSiMg filler metal

  • 摘要: 为丰富SiC陶瓷钎焊所用钎料的设计思路,提出了一种泡沫Ti/AlSiMg新型复合钎料,通过Ti元素的溶入提高钎料与SiC陶瓷之间的界面结合力,利用泡沫Ti与Al基钎料之间的界面反应获得原位增强的钎缝,从而提升接头力学性能. 采用钎焊温度700 ℃、保温时间60 min和焊接压力10 MPa进行SiC陶瓷真空钎焊,利用光学显微镜、扫描电镜、能谱分析、X射线衍射、电子探针和万能试验机对接头组织、成分和性能进行分析,探索泡沫Ti/AlSiMg复合钎料在SiC陶瓷钎焊中的可用性. 结果表明,填充泡沫Ti/AlSiMg复合钎料所得接头结构为SiC/Al/Ti(Al,Si)3/Ti(Al,Si)3原位增强Ti基钎缝/ Ti(Al,Si)3/Al/SiC,断裂发生在铝合金界面层和SiC陶瓷之间,Ti元素的溶入提高了铝合金界面层与SiC陶瓷之间的界面结合力,接头抗剪强度达111 MPa.

     

    Abstract: In order to enrich the design ideas of brazing filler metal for SiC ceramic, a novel Ti foam/AlSiMg composite filler has been proposed. The interfacial adhesion between the filler metal and SiC ceramic was improved by the dissolution of Ti element, and the in-situ reinforced brazing seam was obtained by the reaction between Ti foam and AlSiMg metal which improved the mechanical property of the joint. Vacuum brazing of SiC ceramics was carried out with brazing temperature of 700 ℃, holding time of 60 min and welding pressure of 10 MPa. Microstructure, composition and properties of the joints were analyzed by optical microscope, scanning electron microscope, energy dispersive spectrometer, X-ray diffractometer, electron microprobe analysis, and shearing test. The applicability of Ti foam/AlSiMg filler metal for SiC ceramic brazing was explored. The results show that the structure of the joint with Ti foam/AlSiMg filler was "SiC/Al/Ti(Al,Si)3/ Ti(Al,Si)3 in-situ reinforced Ti based brazing seam/Ti(Al,Si)3/Al/SiC". The fracture occurred between the Al alloy interfacial layer and SiC ceramic. The dissolution of Ti in the liquid Al alloy improved the interfacial adhesion between Al alloy interlayer and SiC ceramic. The shearing strength of the joint with Ti foam/AlSiMg filler metal was 111 MPa.

     

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