Microstructure Evolution and High-Temperature Sliding Wear Behavior of In Situ TiC-Al3Ti Reinforced Aluminum Matrix Composite
摘要
In situ duplex TiC-Al3Ti reinforcements synergistically strengthened aluminum matrix composites exhibit superior mechanical properties; however, the probable formation of the Al4C3 impurity in the Al matrix greatly restricted their practical applications. Herein, the present study focuses on the Ti3AlC2-2024Al composite material, thoroughly investigating the reaction mechanism and phase evolution process of the composite. Meanwhile, the dry sliding friction and wear behavior of this composite material are systematically explored. The results show that at 780 °C, partial Ti3AlC2 decomposes and reacts with 2024Al, facilitating the formation of blocky Al3Ti and ultrafine Al4C3 in the 2024Al matrix. Fortunately, with the rising temperature from 780 to 950 °C, Al4C3 would stepwise react with Al3Ti to form TiC and Al, and the complete elimination of Al4C3 occurred at 950 °C. The sliding wear behavior of the resulting composite at 150 °C indicates that in situ Al3Ti and TiC significantly enhance the thermal stability and load-bearing capacity of the 2024Al matrix. The synergistic effect of the duplex reinforcements effectively reduces the wear rate from 7.2 × 10-4mm3/mN to 4 × 10-4mm3/mN, and the related wear mechanism of TiC-Al3Ti/2024Al composites are determined to be adhesive wear and abrasive wear, respectively.