Kinetics of Interfacial Reaction in SiCf/Ti6Al4V Composites

The Ti6Al4V composites reinforced with Chinese SiC fiber was manufactured and then thermally exposed at 800°C, 900°C and 1000°C, respectively, for up to 500h. The interfacial reaction products were identified as TiC between Ti6Al4V and the C-coating of the SiC fiber. However, if the SiC fiber has no C-coating, the interfacial reaction forms TiC, Ti3SiC2, Ti5Si3(Cx) and Ti3Si(Cx). The thickness of the interfacial reaction zone was measured and it is found that the thickening rate is slower in the samples in which the SiC fiber has the C-coating. The growth of the interfacial reaction products is diffusion-controlled and the parameters of the growth kinetics, k0 and Q, were determined, respectively. The profile of the element distribution was calculated according to the diffusion theory and is well consistent with the expeimental data.