SiCf/Ti-43Al-9V复合材料的界面反应

利用纤维涂层法和真空热压工艺制备SiC纤维增强γ-TiAl金属间化合物(Ti-43Al-9V)复合材料,采用扫描电镜(SEM)、能谱(EDS)、X射线衍射(XRD)仪等研究复合材料的界面反应产物和界面反应产物的生长动力学。结果发现,SiCf/Ti-43Al-9V复合材料的界面反应生成了TiC、Ti2AlC和Ti5Si3,分三层分布。从SiC纤维到Ti-43Al-9V基体,界面反应产物序列为:TiC/Ti2AlC/Ti5Si3+Ti2AlC(颗粒)。界面反应产物的生长受扩散控制并遵循抛物线生长规律,其生长激活能Q和指前因子k0分别为190kJ/mol和2.5×10-5m.s-1/2。与其它Ti合金基的复合材料相比,γ-TiAl基复合材料的界面热稳定性更好。

Interfacial Reaction of SiCf/Ti-43Al-9V Composite

SiC fiber reinforced g-TiAl (Ti-43Al-9V) matrix composite was fabricated by Fiber Coating Method (MCF) plus Vacuum Hot Pressing (VHP). The interfacial reaction products of the composites were identified and the reaction kinetics was studied. According to the analysis results by means of scanning electron microscope, energy dispersive spectrometer and X-ray diffractometer, the interfacial reaction products of TiC, Ti2AlC and Ti5Si3 were formed during the consolidation and the heat treatment of the composite. The reaction products are distributed in three layers of TiC/Ti2AlC/Ti5Si3+Ti2AlC(particle) from SiC fiber side to matrix side. The growth of the interfacial reaction products is controlled by diffusion and follows a rule of parabolic rate. The activation energy Q and the pre-exponential factor k0 of SiCf/Ti-43Al-9V composite are 190 kJ/mol and 2.5×10-5 m·s-1/2, respectively. It is confirmed that the thermal stability of the interface for the present g-TiAl matrix composite is better than that for other Ti alloy matrix composites.