High temperature healing of Ti2AlC: On the origin of inhomogeneous oxide scale

The microstructure of oxide scales formed on Ti2AlC surface after oxidation at 1200 degrees C is investigated. The results reveal an inhomogeneous morphology of the oxide scales, i.e. islands of coarse rutile grains pile up on fine-grained Al2O3 layer. Local cross-sectional observations show that the rutile islands grow on top of cavities in the parent material. A model is proposed to describe the resulting microstructure after oxidation. These results are relevant in optimizing the self-healing conditions of Ti2AlC at high temperature. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.