Crack healing of alumina composites loaded with 5, 10, and 20 vol% Ti2AC (A = Al or Sn) MAX phase was investigated. Surface cracks were prepared by means of indent loading, and the modulus of rupture ...was measured on virgin, indented, and healed specimens. The MAX phase particles serve as a repair filler which reacts with oxygen, penetrating along a surface crack and filling disrupted crack surfaces with the oxidation reaction products. After annealing for 3 h, composites loaded with 20 vol% Ti2AlC showed full recovery at a healing temperature of approximately 900 C, whereas lower temperatures of 700 C were seen for specimens loaded with 10 and 20 vol% Ti2SnC. The enhanced healing response of Ti2AC-loaded composites containing Sn instead of Al on the A-position offers great potential for providing crack healing capability to ceramic matrix composites applied at moderate temperatures below 1000 C.
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