LAUSR

Self-healing materials facilitate a design concept which includes damage management, where damage that is inflicted during operation can be healed autonomously. It has been shown that the Mn+1AXn phases Ti3AlC2, Ti2AlC and Cr2AlC exhibit such behaviour. Cracks are filled and hence healed by oxidation products of the M and A elements in the MAX phase at the high operating temperatures in which they are used. After crack healing the fracture strength is recovered to the level of the virgin material. In this work, the Cr2AlC-MAX phase was shown to exhibit excellent self-healing properties. Cracks of maximum widths of approximately 500 nm and 4 μm could be healed after a 3–5 h anneal at 900 and 1200°C, respectively. In this system, the addition of Y on the rate of oxidation and on the self-healing behaviour was investigated.