As-cast microstructures of Ti-11Al-xC alloys

The investigation of as-cast microstructures of high temperature α+α₂ titanium alloys matrix composites reinforced by particles and fabricated using a reaction synthesis method by XRD, OM and SEM is presented in the paper, which reveals the fact that the matrix transforms into single phase α₂ from two phases α+α₂ and reinforcing phases become Ti₃AlC and TiC from single phase TiC when the C content increases to a critical value, and that Ti₃AlC is precipitated during solidification processing and points out that the morphologies of TiC and Ti₃AlC are of short-lath shape and near spherical shape, respectively, and the lattice parameter of matrix α₂ increase with the increase of C content, but the lattice parameter of reinforcing phase TiC is lower than the standard lattice parameter of TiC due to the C defection in TiC.