Microstructure and dry sliding wear behavior of as-cast TiCp/Ti-1100-0.5Nb titanium matrix composite at elevated temperatures

Abstract

The microstructure and dry sliding wear performance of as-cast TiCp/Ti-1100-0.5Nb composite at 25 °C, 500 °C and 600 °C were systematically investigated. Results show that the solidification matrix microstructure is the typical Widmanstatten structure. The eutectic TiC particles are uniformly distributed in the matrix in the form of feathery, long rod and strip-like shapes. Meanwhile, the interface between TiC and titanium matrix is clear and without any reaction. The wear rate of TiCp/Ti-1100-0.5Nb at 600 °C and 500 °C is reduced by 95.8% and 79.9%, respectively, compared with that of the value of 51.8×10−6 mm3·mm−1 at 25 °C. The friction coefficient of the steady-state period at 25 °C, 500 °C, 600 °C is 0.48, 0.8, 1.2, respectively, and the variation extent of the friction coefficient at elevated temperatures is greater than at 25 °C. The wear mechanism is changed from the mixture of adhesive wear and abrasive wear to mild oxidation wear with rising temperature. It can also be concluded that the composite possesses excellent high temperature wear resistance. The high-wear resistance of the composite is attributed to the Fe2O3 and TiO2. The presence of Fe2O3 and TiO2 reduces the wear rate, increases the friction coefficient, and also improves the range-ability of the friction coefficient.