反应复合钎焊C_f-SiC/Cu-Ti-C/TC4接头组织结构

Microstructure of Reactive Composite Brazing Joints of C_f/SiC Composites and Ti Alloy with Cu-Ti-C Filler Material

研究用Cu粉、Ti粉、石墨粉组成的混合粉末真空钎焊Cf/SiC陶瓷基复合材料和钛合金,采用X射线衍射、扫描电镜和能谱仪对接头组织结构进行分析。结果表明:在Cu-25Ti(质量分数/%)粉末中加入适量石墨,经950℃,20min真空钎焊,获得了完整的原位合成TiC增强的复合接头,连接层中原位合成的一定体积分数的TiC可以明显降低接头热应力。石墨颗粒中的C元素和连接层液相中Ti元素发生相互扩散,形成了残余石墨颗粒周围的TiC反应层和分布在连接层中的TiC颗粒,TiC反应速度主要受C元素由石墨颗粒向连接层液相的扩散速度所控制。

Using the mixed powder of Cu, Ti and graphite Cf/SiC composite was brazed to Ti alloy under vacuum condition. The joints were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. The results show that fine brazed joints of Cf/SiC composite/Ti alloy are acquired at 950℃ for 20rain using Cu-25Ti （mass fraction/%） with the addition of proper graphite as brazing alloy. Iresitu synthesized TiC which reduces the thermal stress significantly is obtained during vacuum brazing. TiC reaction layer around surplus graphite and TiC particles in the bonding layer are synthesized by interdiffusing of C element and Ti element in the liquid bonding layer. The reaction rate is controlled by the diffusion rate of C element from graphite particles to liquid bonding layer.