Reactive synthesis of polycrystalline Ti3AlC2 and its sintering behavior

Abstract:

A method for fabrication of ternary compound Ti3AlC2 powder by presureless calcining (PC) technique was developed. Powders of Ti, Al and TiC were mixed as staring materials. The effect of calcining temperatures and aluminum content on the purity of Ti3AlC2 was discussed in detail. The reaction mechanism and the microstructure evolution of Ti3AlC2 prepared at different temperature were investigated by X-ray diffraction, field emission scanning electron microscopy and high resolution transmission electron microscopy. Results indicate that the single-phase polycrystalline Ti3AlC2 powder was obtained at 1300 ℃, which perform a typical laminated structure, and the best molar ratio of raw Ti/Al/TiC materials was 1:1.2:2. The bulk samples sintered by hot pressing were using the Ti3AlC2 powder. After hot pressing of different temperature, the fully dense of bulk Ti3AlC2 showed the best properties prepared at 1300 ℃. The density of bulk Ti3AlC2 reached to 99.9%. The average Vickers hardness was around 5.7 GPa, and the maximum flexural strength was over 630 MPa. Finally the strengthening mechanism of the bulk Ti3AlC2 was also proposed.

Key words:Ti₃AlC₂;reaction mechanism; sintering behavior