Microstructure and mechanical properties of micro-nano particles reinforced TiAl composites at room temperature

Abstract:

The mixed powders of Ti-48Al-2Nb-2Cr alloy with multilayer graphene oxide, SiC particles and BN nanosheets were sintered by spark plasma sintering (SPS) at 1300 ℃, and the different reinforcement on microstructure evolution and properties of TiAl composites were investigated. The results showed that the microstructure of composites was significantly changed with the addition of different reinforcement. The micro-nano Ti₂AlC in-situ precipitated at the interface of α₂ lath and γ lath of TiAl matrix after adding graphene. While a microstructure composed of networked core-shell (CS) structured cells can be formed in TiAl matrix with the addition of SiC particles and BN nanoplatelets. Moreover, Ti₂AlC can be in situ precipitated and CS structure can be formed by adding graphene and BN nanoplatelets simultaneously. The compressive properties and wear properties of TiAl composites were improved significantly, which showed optimal performance by adding graphene and BN nanoplatelets simultaneously. TiAl composites provided a new idea for alloy designation and broken through the performance limitation of TiAl alloy.

Key words:Composite materials; TiAl alloy; SPS; mechanical properties