Producing Ti-6Al-4V/TiC composite with superior properties by adding boron and thermo-mechanical processing

In order to study the effect of boron addition on the microstructure and tensile properties of titanium matrix composites, two Ti-6Al-4V/10 Vol% TiC ingots with and without boron were fabricated by VIM furnace and hot rolling. The microstructures of composites were examined using optical microscopy (OM). The X-ray diffraction (XRD) was used to identify the phases present in the composites. Addition of boron resulted in the formation of needle shaped TiB in the matrix that was followed by the refinement of grain size. Compared with Ti-6Al-4V/TiC composite, the composite containing boron content exhibited a significantly higher ductility and lower strength. It was caused by the effects of boron element on reducing TiC particle size and solubility of carbon in alpha matrix. According to the results obtained in this study, the hybrid effect of TiC and TiB plays an important role in the mechanical properties, especially ductility of titanium matrix composites (TMCs). Finally, we have produced TMCs strip with excellent ductility (9% elongation and 18% reduction area) and good strength (∼1240 MPa).