Enhancing the wear performance of Ti-6Al-4V against Al2O3 and WC-6Co via TiBn layer produced by boriding

Abstract

Abstract In this study, mechanical and tribological properties of the borided dual-phase α + β type Ti6Al4V titanium alloy were examined. For this purpose, Ti6Al4V alloy samples were borided for 6 h at a temperature of 1100 °C by the powder-pack boriding process. As a result of boriding, a boride layer consisting of TiB2 with a thickness of max ∼25 µm and TiB phases with a thickness of max ∼10 µm was obtained on the Ti6Al4V sample surfaces. As a result of the boride layer’s nanoindentation tests carried out using the Berkovich indenter, it was found to have an elastic modulus of 534.255 GPa and a hardness of 36.537 GPa. Wear tests were carried out using the pin-on-disc method under a load of 10 N and with a sliding distance of 1000 m. Whereas the dominant type of wear in non-borided samples was abrasive wear, oxidative mild wear was generally observed in borided samples. In borided samples, as a result of becoming of surface smoother by hard asperities breaking and increasing the actual contact area, the friction coefficients increased. It was determined that with boriding, the wear performance of Ti6Al4V alloy improved ∼46.8 times against the Al2O3 counterpart and ∼4.57 times against WC-6Co counterpart.