Microstructure, mechanical and tribological properties of TiAl-based composites reinforced with high volume fraction of nearly network Ti2AlC particulates

TiAl-based composites reinforced with different high volume fractions of nearly network Ti2AlC phase have been successfully prepared by mechanical alloying and hot-pressing method. Their microstructure, mechanical and tribological properties have been investigated. Ti2AlC network becomes continuous but the network wall grows thicker with increasing the Ti2AlC content. The continuity and wall size of the network Ti2AlC phase exert a significant influence on the mechanical properties. The bending strength of the composites first increases and then decreases with the Ti2AlC content. The compressive strength of the composite decreases slightly compared to the TiAl alloy, but the hardness is enhanced. Due to the high hardness and load-carrying capacity of the network structure, these composites have the better wear resistance. And this enhancement is more notable at low applied loads and high Ti2AlC content. The mechanisms simulating the role of network Ti2AlC phase on the wear behavior and the wear process of TiAl/Ti2AlC composites at different applied loads have been proposed.