Tribological behavior of Ti-Al-Nb alloy with different Ta additions for high temperature applications

In this study the wear behavior of the Ti-Al-Nb alloy with 0???7 at% Ta addition was investigated. For this purpose, the Ti-Al-Nb-Ta alloys were prepared by mechanical alloying and spark plasma sintering (SPS). Wear tests were done under 50, 100, and 150 N at room temperature (RT) and 600 ???C. Results showed that at high temperatures the wear rate (WR) and coefficient of friction (COF) were reduced significantly. SEM micrographs and phase analysis of the worn surface indicated that TiO2 , TaO2/Ta2O5 , AlTaO4 , and TiNbO4 phases created during wear test cases the excellent self-lubricant properties. Furthermore, indicated that by increasing Ta content the WRs were decreased due to increased TaO2 and AlTaO2 phases.