Microstructure and properties of Ti3AlC2 prepared by the solid–liquid reaction synthesis and simultaneous in-situ hot pressing process

The microstructure of polycrystalline Ti3AlC2 fabricated by the solid-liquid reaction synthesis and simultaneous in-situ hot pressing process was investigated by SEM and TEM. It is revealed that the Ti3AlC2 grains are plate-like with a high density of stacking faults and dislocations predominantly lying within (0001) planes. The mechanical, electrical properties and oxidation behavior of fully dense Ti3AlC2 fabricated by this newly developed method were also investigated. Ti3AlC2 was relatively soft with Vickers hardness ranging from 2.5 to 4.7 GPa. The flexural strength and the fracture toughness were 340 MPa and 7.2 MPa-m(1/2), respectively. Ti3AlC2. had high compressive strength at both room and high temperatures, and its failure below 1000 degreesC was shear fracture, while above 1050 degreesC the deformation was ductile. Ti3AlC2 had good resistance to thermal shock. The electrical conduction of Ti3AlC2 was metallic with room-temperature electrical conductivity of 3.48 x 10(6)Omega(-1)m(-1). The isothermal oxidation of Ti3AlC2 at 1000-1400 degreesC in air revealed that it had excellent oxidation resistance and obeyed a cubic law, and adhesive continuous Al2O3 layer formed on Ti3AlC2. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.