The effect of TiC on microstructure and mechanical properties of Ti-5553 beta phase titanium alloy

Abstract

The presence of TiC in Ti alloys is ubiquitous, so, for the interest of exploring its effects, carbon is added in Ti-5553 (beta phase alloy). After fabrication, sintering and multi heat treatments are done to get desired microstructure (TiC in beta, alpha and alpha-matrix). Quasi-static compression, three-point bend test, nano-indentation, and abrasion tests are conducted to study the microstructural response. Different analyzing tools such as SEM, EDS, EBSD, and HRTEM are used to examine microstructural changes before and after fracture. Results showed that TiC crystals are hard and brittle, and favorite sites for crack nucleation and propagation. After comparing both the curves and their corresponding micrographs, it is concluded that the propagation speed of the crack is much faster in TiC as compared to the beta and alpha phases. Furthermore, an increase in the value of strain upon reaching a crack at the TiC/Tiᵦ, and TiC/Tiα interface justifies that these phases offer comparatively more toughness and ductility. In addition, the presence of these crystals in the beta phase initiate fracture almost within half of the elastic limit of Ti-5553 beta phase alloy. Conclusively, TiC has an adverse effect on titanium's mechanical properties if shape and size are not controlled.