Tribological investigations of boride layers on Ti6Al4V at room and elevated temperatures

Abstract

PurposeThis paper aims to improve the wear resistance of titanium alloy using a high-hardness boride layer, which was fabricated on Ti6Al4V by a high-temperature boronizing process.Design/methodology/approachThe boride layers on Ti6Al4V were obtained at 1000°C for 5–15 h. Scanning electron microscopy, energy dispersive analysis and X-ray diffractometer were used to characterize the properties of the boride layer. The tribological performance of the boride layer at room and elevated temperatures was investigated.FindingsThe X-ray diffraction analysis showed that the boride layers were a dual-phase structure of TiB and TiB2. When the boronizing time increased from 5 h to 15 h, the microhardness increased from 1192 HV0.5 to 1619.8 HV0.5. At 25°C and elevated temperatures, the friction coefficients of the boride layers were higher than that of Ti6Al4V. The wear track areas of T-5 at 200°C and 400°C were 2.5 × 10–3 and 1.1 × 10–3 mm2, respectively, which were 6.1% and 2.6% of that of Ti6Al4V, indicating boride layer exhibited a significant wear resistance. The wear mechanisms of the boride layer transformed from slight peeling to oxidative wear and abrasive wear as the temperature was raised.Originality/valueThe findings provide an effective strategy for improving the wear resistance of Ti6Al4V and have important implications for the application of titanium alloy in a high-temperature field.