Microstructure and mechanical properties of Ti matrix composite reinforced with 5 vol.% TiC after various thermo-mechanical treatments

In this work, Ti matrix composite reinforced with 5 vol % TiC ceramic was prepared using in situ technologies, then various microstructures of the composite were obtained after it was treated with thermo-mechanical treatments applied in different temperature ranges with different deformation amplitudes. Widmanstatten, bimodal or fined α laths microstructure was obtained after it was treated by thermo-mechanical treatment performed in β phase field, in α+β phase field or in upper α phase field, respectively. The measured β transfuse temperature of the composite rises about 100 K compared to that of the monolithic matrix alloy, which resulted from the carbon solid solution of the matrix. The results of tensile tests showed that the composite strength was increased after the thermo-mechanical treatment, and the increase may be attributed to the effects of the load transfer from matrix to TiC particles and the refinement of the matrix microstructure. The TEM observation shows that the size of α colonies takes an important role to the equivalent grain size of the matrix, but the size of the thickness of α plates has minor effect on it.