TY - JOUR
T1 - Autonomous high-temperature healing of surface cracks in Al2O3 containing Ti2AlC particles
AU - Boatemaa, Linda
AU - Bosch, Myrthe
AU - Farle, Ann Sophie
AU - Bei, Guo Ping
AU - van der Zwaag, Sybrand
AU - Sloof, Willem G.
PY - 2018
Y1 - 2018
N2 - In this work, the oxidation-induced crack healing of Al2O3 containing 20 vol.% of Ti2AlC MAX phase inclusions as healing particles was studied. The oxidation kinetics of the Ti2AlC particles having an average diameter of about 10 μm was studied via thermogravimetry and/or differential thermal analysis. Surface cracks of about 80 μm long and 0.5 μm wide were introduced into the composite by Vickers indentation. After annealing in air at high temperatures, the cracks were filled with stable oxides of Ti and Al as a result of the decomposition of the Ti2AlC particles. Crack healing was studied at 800, 900, and 1000°C for 0.25, 1, 4, and 16 hours, and the strength recovery was measured by 4-point bending. Upon indentation, the bending strength of the samples dropped by about 50% from 402 ± 35 to 229 ± 14 MPa. This bending strength increased to about 90% of the undamaged material after annealing at 1000°C for just 15 minutes, while full strength was recovered after annealing for 1 hour. As the healing temperature was reduced to 900 and 800°C, the time required for full-strength recovery increased to 4 and 16 hours, respectively. The initial bending strength and the fracture toughness of the composite material were found to be about 19% lower and 20% higher than monolithic alumina, respectively, making this material an attractive substitute for monolithic alumina used in high-temperature applications.
AB - In this work, the oxidation-induced crack healing of Al2O3 containing 20 vol.% of Ti2AlC MAX phase inclusions as healing particles was studied. The oxidation kinetics of the Ti2AlC particles having an average diameter of about 10 μm was studied via thermogravimetry and/or differential thermal analysis. Surface cracks of about 80 μm long and 0.5 μm wide were introduced into the composite by Vickers indentation. After annealing in air at high temperatures, the cracks were filled with stable oxides of Ti and Al as a result of the decomposition of the Ti2AlC particles. Crack healing was studied at 800, 900, and 1000°C for 0.25, 1, 4, and 16 hours, and the strength recovery was measured by 4-point bending. Upon indentation, the bending strength of the samples dropped by about 50% from 402 ± 35 to 229 ± 14 MPa. This bending strength increased to about 90% of the undamaged material after annealing at 1000°C for just 15 minutes, while full strength was recovered after annealing for 1 hour. As the healing temperature was reduced to 900 and 800°C, the time required for full-strength recovery increased to 4 and 16 hours, respectively. The initial bending strength and the fracture toughness of the composite material were found to be about 19% lower and 20% higher than monolithic alumina, respectively, making this material an attractive substitute for monolithic alumina used in high-temperature applications.
KW - alumina
KW - MAX phase
KW - oxidation kinetics
KW - self-healing
KW - TiAlC
UR - http://resolver.tudelft.nl/uuid:a3fcbbc4-c9ca-4ef7-a422-56980bcb9798
UR - http://www.scopus.com/inward/record.url?scp=85045640811&partnerID=8YFLogxK
U2 - 10.1111/jace.15793
DO - 10.1111/jace.15793
M3 - Article
AN - SCOPUS:85045640811
SN - 0002-7820
VL - 101
SP - 5684
EP - 5693
JO - Journal of the American Ceramic Society
JF - Journal of the American Ceramic Society
IS - 12
ER -