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Strength recovery of machined Al 2 O 3 /SiC composite ceramics by crack healing
Author(s) -
ONO M.,
NAKAO W.,
TAKAHASHI K.,
ANDO K.
Publication year - 2007
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2007.01182.x
Subject(s) - materials science , machining , composite material , fracture toughness , composite number , ceramic , flexural strength , fracture (geology) , metallurgy
Alumina is used in various fields as a machine component. However, it has a low fracture toughness, which is a weakness. Thus, countless cracks may be initiated randomly by machining, and these cracks decrease the component's mechanical properties and reliability. To overcome this problem, a crack‐healing ability could be a very useful technology. In this study, Al 2 O 3 /SiC composite was sintered. This alumina exhibits excellent crack‐healing ability. Small specimens for a bending test were made from the Al 2 O 3 /SiC. A semicircular groove was machined using a diamond ball‐drill. The machining reduced the local fracture stress from approximately 820–300 MPa. The machined specimens were crack‐healed under various conditions. The fracture stress of these specimens after crack healing was evaluated systematically from room temperature (RT) to 1573 K. It was found that the local fracture stress of the machined specimen recovered almost completely after crack healing. Therefore, it was concluded that crack healing could be an effective method for improving the structural integrity of machined alumina and reducing machining costs.