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Licensed Unlicensed Requires Authentication Published by De Gruyter May 26, 2013

Fracture Toughness of Alumina Ceramics Determined by Vickers Indentation Technique

Bestimmung der Bruchzähigkeit von Aluminiumoxidkeramiken mittels Vickers Härtemessung
  • Marijana Majić and Lidija Ćurković
From the journal Materials Testing


Fracture toughness (KIC) of high purity cold isostatically pressed alumina ceramic (CIP-Al2O3) was determined from the size of cracks induced by Vickers hardness testing at wide range of loads. The observed cracks appeared at following loads: 4.905 N, 9.81 N, 29.43 N and 49.05 N. The studied material exhibits half-penny crack system at lower load of 4.905 N, but it proceeds as the Palmqvist crack system at higher loads, which was determined computationally. For the fracture toughness calculation different models were compared. It was found that fracture toughness increases by rising applied load for all kind of models, which is explained by the indentation size effect. As the fracture toughness overestimation can lead to product malfunction, it is suggested to use the Niihara model, which gives the smallest fracture toughness values.


Die Bruchzähigkeit KIC von hochreiner isostatisch kaltgepresster Aluminiumoxidkeramik (CIP-Al2O3) wurde anhand der Rissgröße bestimmt, die durch Vickershärtemessungen bei einer großen Bandbreite von Lasten induziert wurde. Die Risse traten bei den folgenden Lasten auf: 4,905 N, 9,81 N, 29,43 N und 49,05 N. Die untersuchten Materialien weisen ein so genanntes Half-Penny-Risssystem bei niedrigeren Lasten von 4,905 N auf. Es schreitet jedoch im Palmquvist-Risssystem bei höheren Lasten fort, was rechnerisch ermittelt wurde. Für die Berechnung der Bruchzähigkeit wurden verschiedene Modelle verglichen. Es wurde herausgefunden, dass die Bruchzähigkeit mit zunehmender angelegter Last in allen angewandten Modellen steigt, was mit der Größe des Indenters erklärt wurde. Da eine Überschätzung der Bruchzähigkeit zu einem Funktionsausfall eines Produktes führen kann, wird vorgeschlagen das Niihara Modell zu verwenden, das die niedrigsten Bruchzähigkeitswerte liefert.

Marijana Majić, born 1985, achieved master's degree in mechanical engineering, at the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb. She is employed as research assistant/scientific novice at the same institution, at the Department of Materials. She is postgraduate student of material science and engineering at the Faculty of Mechanical Engineering and Naval Architecture.

Lidija Ćurković, born 1966, graduated at the Faculty of Chemical Engineering and Techno­logy, University of Zagreb in 1990. After gra­duating she worked at the Department of Analytical Chemistry at the same faculty. In 1995 she acquired the Master's degree and the Doctor's degree in 1999 at the Faculty of Chemical Engineering and Technology in Zagreb. Since 2000 she has been working at the Department of Materials of the Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb. She is now associate professor and Head of Laboratory for Chemical Analysis of Metals at Faculty of Mecha­nical Engineering and Naval Architecture, University of Zagreb. The scientific work includes research in the field of material science and engineering, particularly ceramics and ceramic coating.


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Published Online: 2013-05-26
Published in Print: 2012-04-01

© 2012, Carl Hanser Verlag, München

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