Abstract
Tribological behavior of the isothermally forged and heat-treated Ti-22Al-25Nb (at. %) orthorhombic alloy with lamellar O microstructures was investigated. The friction experiments using a tribometer (UMT-3 CETR) against Si3N4 and Al2O3 were conducted at the load of 10N from 20 to 750 °C and a constant speed of 0.188 m/s. The experiment results indicated that for the friction pair of Al2O3, the coefficient of friction (COF) was decreased from 0.906–0.359, and for the friction pair of Si3N4, COF was decreased from 0.784–0.457 as the friction temperature increased from room temperature to 750 °C. The wear rate of the alloy against Al2O3 is in the range of 2.63–8.15 × 10−4 mm3N−1m−1, the wear rate against Si3N4 is in the range of 2.44–5.83 × 10−4 mm3N−1m−1, respectively. The wear mechanisms of the alloy were changed from plastic deformation and ploughing at lower temperature (20–400 °C) to adhesive wear and oxidative mechanism at higher temperature (600 and 750 °C). The friction and wear behavior of the Al2O3 friction pair was comparable to that of the Si3N4 friction pair.
Highlights
Among titanium aluminides, the orthorhombic Ti2 AlNb-based alloys have higher ductility, higher yield strength, and better elevated temperature strength and fracture toughness [1,2,3]
The Ti2 AlNb-based alloys can be used as the rotating components like turbine blades and valves, in this situation, this alloy will be subjected to friction and wear
The aim of this paper is to study the friction and wear of the Ti-22Al-25Nb orthorhombic alloy which produced by casting and forging
Summary
The orthorhombic Ti2 AlNb-based alloys have higher ductility, higher yield strength, and better elevated temperature strength and fracture toughness [1,2,3]. Considerable interest has been given to the Ti2 AlNb-based alloys for various applications in aerospace components [4,5]. Many aviation components which were made by Ti2 AlNb-based alloys are fitted in a trial run engine [8]. The Ti2 AlNb-based alloys can be used as the rotating components like turbine blades and valves, in this situation, this alloy will be subjected to friction and wear. Wear resistance of Ti2 AlNb-based alloys is much lower. This problem limited some practical applications of the Ti2 AlNb-based alloys at high temperatures. It is very important to investigate the high-temperature tribological properties of Ti2 AlNb-based alloys [10]
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