engleski

Fracture toughness of alumina ceramics determined by indentation technique

Fracture toughness (KIC) of high purity cold isostatically pressed alumina ceramics was determined from the size of cracks induced by Vickers hardness testing at the wide range of loads. The observed cracks appeared at following loads: 4.905, 9.81, 29.43 and 49.05 N. For the fracture toughness calculation different models were compared. It was found that fracture toughness increases by increasing applied load for all applied models, which is explained by the indentation size effect. The fracture toughness overestimation can lead to product malfunction. Therefore, the use of the Anstis model, which gives the smallest fracture toughness values, is suggested.

fracture toughness ; alumina ceramics ; Vickers hardness ; indentation technique

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