Microhardness,compression performance and high-temperature tribological properties of Ti2AlNb-silver self-lubricating composite

The Ti₂AlNb-based self-lubricating composite material reinforced with silver particles of 0 wt% to 15 wt% was prepared by spark plasma sintering, and the microhardness, compression performance and high-temperature tribological properties were investigated. The results show that the silver is distributed in the Ti₂AlNb matrix as small islands. The microhardness reaches the maximum at 5 wt% silver content but then decreases sharply. The compressive strength is reduced due to the silver-rich areas have become the initiation points of cracks, and the softening of silver at high temperatures intensifies the process. The friction coefficient and wear rate of the composite material at 500 °C are significantly reduced by silver, and the lubrication mechanism is attributed to the synergistic effect of silver and oxides.