CRACK HEALING IN AL
2O
3COMPOSITE MATERIALS USING TI
2ALC
AS REPAIR FILLER
B.J. Pedimonte1, G.P. Bei1, T. Fey1 and P. Greil1 1
University of Erlangen-Nuernberg, Department of Materials Science (Glass and Ceramics), Martensstr. 5, D-91058 Erlangen, Germany - e-mail: Guoping.Bei@ww.uni-erlangen.de; Joana.Pedimonte@ww.uni-erlangen.de; Tobias.Fey@ww.uni-erlangen.de; Peter.Greil@ww.uni-erlangen.de
Keywords: ceramics, crack healing, repair filler, strength recovery
ABSTRACT
Oxide ceramics such as Al2O3 may undergo crack-healing when exposed to
temperatures exceeding 1400 °C. In order to reduce healing temperature repair fillers based on nanolaminate MAX-phase in the system Ti-Al-C were dispersed in Al2O3
matrix. In contrast to solid-state sintering process requiring high activation energy, oxidation reaction of repair filler facilitates filling of disrupted cracks with oxidation product at significant lower temperatures.
Al2O3-MAX phase composites, loaded with 10-20 vol% Ti2AlC were fabricated by
pressureless sintering at 1400°C. Cracks were prepared by indentation. Strength recovery was analyzed after annealing at various temperatures (600 - 1000°C) and times (1 - 10h). Critical conditions to achieve crack healing were derived from microstructure and fracture surface analyses.
