Reaction diffusion in continuous SiC fiber reinforced Ti matrix composite

摘要

SiC continuous fiber-reinforced pure Ti(TA1)matrix composites were fabricated by a vacuum hot pressing(VHP)methodand then heat-treated in vacuum under different conditions.The interfacial reaction and the formation of interfacial phases werestudied by using SEM,EDS and XRD.The results show that there exists reaction diffusion at the interface of SiC fibers and Timatrix,and the concentration fluctuation of reaction elements such as C,Ti and Si appears in interfacial reaction layer.The interfacialreaction products are identified as Ti3SiC2,TiCx and Ti5Si3Cx.At the beginning of interfacial reaction,the interfacial reactionproducts are TiCx and Ti5Si3Cx.Along with the interfacial reaction diffusion,Ti3SiC2 and Ti5Si3Cx single-phase zones come forth inturn adjacent to SiC fibers,and the TiC+Ti5Si3Cx double-phase zone appears adjacent to Ti matrix,which forms discontinuousconcentric rings by turns around the fibers.The formed interfacial phases are to be Ti3SiC2,Ti5Si3Cx and TiCx+Ti5Si3Cx from SiCfiber to Ti matrix.The interfacial reaction layer growth is controlled by diffusion and follows a role of parabolic rate,and theactivation energy(Qk)and(k0)of SiC/TA1 are 252.163 kJ/mol and 7.34×10?3m/s1/2,respectively.