ZrB2-SiC陶瓷复合材料钎焊接头界面组织及性能

采用BNi₂钎料,对ZrB₂-SiC陶瓷复合材料进行真空钎焊研究.借助SEM,EDS,XRD等分析测试手段分析了界面组织结构及性能.确定了最佳钎焊工艺参数:钎焊温度1160℃,保温时间20 min.结果表明,接头界面产物主要有δ-Ni₂Si,β₁-Ni₃Si,ZrB₂+C,Ni(s,s),Cr_xB_yC_z.随着钎焊温度升高以及保温时间的延长,接头抗剪强度均先升高后降低.钎焊温度1160℃,保温时间20 min,钎焊接头室温抗剪强度达到最大121.3 MPa.钎焊温度和保温时间对接头断裂方式的影响有相似的规律,在保温时间较短时,裂纹主要产生于钎缝中的Ni(s,s)中,之后向Ni元素扩散层中扩展;当保温时间适中时,断裂主要发生在Ni元素扩散层中;当保温时间延长时,裂纹主要产生于含有一定β₁-Ni₃Si相的Ni(s,s)中,之后向Ni元素扩散层中扩展.

Microstructure and mechanical properties of ZrB2-SiC ceramic composite brazed joint

The ZrB₂-SiC ceramic matrix composites were joined by vacuum brazing with BNi₂ filler metal. SEM,EDS and XRD were used to analyze the interface microstructure and properties. The optimized brazing parameters were 1 160℃ of brazing temperature and 20 min of holding time. The experimental results show that the interface products were mainly δ-Ni₂Si,β₁-Ni₃Si,ZrB₂+C,Ni(s,s) and Cr_xB_yC_z phases. With the increase of brazing temperature and holding time, the shear strength of the joint increased first and then decreased. The maximum shear strength of the joint brazed at 1 200℃ for 20 min reached 121 MPa. The effect of brazing temperature and holding time on the joint fracture mechanism was similar. When the holding time was short,cracks mainly occurred at Ni(s,s) in the seam,and then propagated to the Ni diffusion layer. When the holding time was suitable,the fracture mainly occurred in the Ni diffusion layer. When the holding time increased further, cracks mainly initiated in the Ni(s,s) with some β₁-Ni₃Si and later developed to the Ni diffusion layer.