In Situ Synthesis of Hybrid-reinforced Titanium Matrix Composites

摘要

Novel hybrid TiB, TiC and rare earth oxide (Re_2O_3) reinforced titanium matrix composites were in situ synthesized utilizing the reaction between Ti, B_4C (or C), rare earth (Re) and B_2O_3 through homogeneously melting in a non-consumable vacuum arc remelting furnace. In this work, Nd and Y were chosen as rare earth (Re) added in the in situ reaction. The thermodynamics of in situ synthesis reaction was studied. The results of X-ray diffraction (XRD) proved that no other phases appeared except for TiB, TiC and Re_2O_3. The microstructures of the composites were examined by scanning electron microscope (SEM) and backscattered scanning electron microscope (SEM). The results showed that there were mainly three kinds of reinforcements: TiB whiskers, TiC particles and Re_2O_3 particles. The reinforcements were fine and were homogeneously distributed in the matrix. The interfaces of TiB-TiC and Nd_2O_3-Ti were examined by high-resolution transmission electron microscopy (HREM).Transmission electron microscopy (TEM) and selected area diffraction (SAD) were used to analyze the orientation relationships of TiB-TiC and Nd_2O_3-Ti. The orientation relationship between TiB and TiC can be described as: [001]_(TiB) //[001]_(TiC), (010)_(TiB)//(110)_(TiC). The orientation relationship of Nd_2O_3 and α-Ti can be described as: [110]_(Nd_2O_3) //[1213]_(Tt), (111)_(Nd_2O_3)//(1101)_(Ti),(001)_(Nd_2O_3)//(2110)_(Ti).