In Situ Synthesis of Hybrid-Reinforced Titanium Matrix Composites

Abstract

Novel hybrid TiB, TiC and rare earth oxide (Re2O3) reinforced titanium matrix composites were in situ synthesized utilizing the reaction between Ti, B4C (or C), rare earth (Re) and B2O3 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 Re2O3. 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 Re2O3 particles. The reinforcements were fine and were homogeneously distributed in the matrix. The interfaces of TiB-TiC and Nd2O3-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 Nd2O3-Ti. The orientation relationship between TiB and TiC can be described as: [001] TiB //[001] TiC , (010) TiB //(110) TiC . The orientation relationship of Nd2O3 and α-Ti can be described as: [110] Nd2O3 //[ 1213 ] Ti , (111) Nd2O3 //(1101) Ti , ( 001) Nd2O3 //( 2110 ) Ti .