Cu-Ti-C反应复合-扩散连接Cf/SiC复合材料和TC4钛合金接头的组织结构

Microstructure of Reactive Composite Brazing Joints of Cf/SiC Composite to Ti-6Al-4V Alloy with Cu-Ti-C Filler Material

摘要:

用Cu粉、Ti粉、石墨粉组成的混合粉末连接Cf/SiC陶瓷基复合材料和TC4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-(15~30)Ti（ω, %）粉末中加入适量石墨粉作钎料，经900~950 ℃、5~30 min真空钎焊，获得了完整的原位合成TiC增强的复合接头。通过在连接层中原位合成一定体积分数TiC可以明显降低接头热应力。钎料石墨颗粒中的C元素和液相连接层中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。反应速率主要受C元素由石墨颗粒向液相连接层的扩散速率所控制。

Abstract:

Using the mixed powders of Cu, Ti and graphite, Cf/SiC composite was brazed to Ti-6Al-4V alloy under vacuum condition. The joint microstructures were investigated by X-ray diffractrometry, scanning electron microscopy and energy dispersive spectrometry. The results showed that fine brazed joints of Cf/SiC composite/Ti alloy were acquired at 900~950 ℃ for 5~30 min using Cu-(15~30wt%)Ti with the addition of proper amount of graphite powder as brazing alloy. In-situ synthetic TiC which reduces the thermal stress significantly was obtained during vacuum brazing. TiC reaction layer around surplus graphite and TiC particles in the bonding layer was synthesized by interdiffusing of C element and Ti element in the liquid bonding layer. The reaction rate could be controlled by the diffusion rate of C element from graphite particles to liquid bonding layer.