Oxidation-induced crack healing in Ti3AlC2 ceramics

Crack healing of Ti3AlC2 was investigated by oxidizing a partially pre-cracked sample. A crack near a notch was introduced into the sample by tensile deformation. After oxidation at 1100 degrees C in air for 2 h, the crack was completely healed, with oxidation products consisting primarily of alpha-Al2O3 as well as some rutile TiO2. The indentation modulus and hardness of the crack-healed zone are slightly higher compared with those of the Ti3AlC2 base material. The preferential oxidation of Al atoms in Ti3AlC2 grains on the crack surface results in the predominance of alpha-Al2O3 particles forming in a crack less than 1 mu m wide. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.