Microstructure, Hardness, and Wear Assessment of Spark-Plasma-Sintered Ti-xAl-1Mo Alloy

Abstract

Alloys from the Ti-Al-Mo ternary system are of high importance in aerospace applications due to their excellent specific strength-to-density ratio, excellent corrosion, and creep resistance up to 600 °C. However, their sliding wear behavior has not been adequately explored. Cp-Ti and Ti-xAl-1Mo (x = 3, 5, 7) based near-alpha titanium alloys were successfully compacted by spark plasma sintering. The effect of Al addition on the densification, microhardness, and wear behavior of the developed alloys was studied. Results from the experiment showed that all compacts were almost fully densified. An increase in the value of the microhardness was recorded from 208 ± 10 to 352 ± 17 HV as the Al content increased. Al additions played an important role in the wear performance of the sintered alloy as detected from the coefficient of friction obtained with the sliding time and varying normal load. The alloyed Ti compacts had improved wear resistance. The wear rate values of alloyed compacts were 14 to 48.54 pct lower compared to the sintered Cp-Ti compacts tested as the Al content increased. The best wear resistance was observed for Ti-7Al-1Mo. Scanning electron microscopy micrographs, energy-dispersive spectroscopy, and wear debris show that the major wear mechanism detected was adhesive wear.