真空无压钎焊原位生成Ti_(3)SiC_(2)相连接SiC及其力学性能研究

Study on Joining Si C with Ti_3SiC_(2) Phase In-situ Formed by Vacuum Pressureless Brazing and Its Mechanical Properties

使用TiSi_(2)粉与Si粉混合钎料对SiC进行真空无压钎焊,实现了SiC陶瓷的连接。通过微观组织表征揭示了不同连接温度与保温时间下的焊缝组织演变规律,并测试了不同钎焊工艺下的SiC接头常温力学性能。结果显示:在1400℃保温3 h或在1500℃保温2 h,钎料可与SiC发生原位反应生成致密连续的Ti_(3)SiC_(2)(MAX)相,连接温度的提升可以缩短MAX合成所需要的保温时间。1400℃下保温3 h及1500℃下保温2 h所获SiC接头平均室温剪切强度分别为98、151 MPa。1500℃所获接头焊缝与SiC陶瓷基体形成了锯齿状的界面,增强了焊缝与母材的机械连接强度。

The vacuum brazing of SiC was carried out with TiSi_(2) powder and Si powder mixed filler metal,and the connection of SiC ceramics was realized.The microstructure evolution of SiC joints under different joining temperatures and holding time was revealed by microstructure characterization,and the normal temperature mechanical properties of SiC joints under different brazing processes were tested.The results show that under 1400 ℃ for 3 h or 1500 ℃ for 2 h,the filler metal can react with SiC in situ to form dense and continuous Ti_3SiC_(2) (MAX) phase,the increase of joining temperature can shorten the holding time needed for MAX synthesis.The average room temperature shear strength of SiC joints held at 1400 ℃ for 3 h and 1500℃ for 2 h is 98,151 MPa,respectively.The weld joint obtained at 1500 ℃ forms a serrated interface with the SiC ceramic matrix,which enhances the mechanical connection strength between the weld and the base metal.