Joining of C/C Composites and GH3128 Ni-based Superalloy with Ni-Ti Mixed Powder as an Interlayer

摘要:

通过包埋工艺在C/C复合材料表面制备了改性SiC涂层。采用Ni-Ti粉末作中间层连结材料，利用真空热压扩散工艺成功制备了SiC涂层改性C/C复合材料与GH3128镍基高温合金的连接样件。借助X射线衍射仪、扫描电子显微镜、能谱分析仪和材料万能试验机，研究了SiC涂层改性C/C复合材料与GH3128镍基高温合金连接接头及其界面的元素分布、微观结构及力学性能。结果表明，在C/C复合材料表面制备SiC涂层，不仅充分改善了C/C复合材料对Ni-Ti中间层连结材料的润湿性，而且还有效缓解C/C复合材料与GH3128连接界面因热膨胀不匹配而造成的热应力。经过SiC涂层改性处理的连接接头，其室温剪切强度可达22.49 MPa；而没有经过SiC涂层改性处理的连接接头，其室温剪切强度几乎为零。

Abstract:

A modified SiC coating was prepared on the surface of C/C composites by a pack cementation process. Ni-Ti mixed powder was used as an interlayer to join SiC coating modified C/C composites and GH3128 Ni-based high-temperature alloy (GH3128) by a vacuum hot-pressing diffusion process. The chemical element distribution, microstructure and mechanical properties of the joint between C/C composites and GH3128 were investigated by X-ray diffractometry, scanning electron microscopy, energy-dispersive spectrometry and material universal testing machine. Results show that the SiC modified coating on the surface of C/C composites not only improves fully the wettability of C/C composites to the Ni-Ti intermediate layer, but also alleviates effectively the thermal stress in the joint due to mismatch thermal expansion. Under the same joining condition, the shear strength of the joint with SiC modified coating at room temperature is up to 22.50 MPa, whereas that of the joint without SiC coating modification is almost 0.