プレクラック導入試片を用いた構造用セラミックスの破壊靱性評価

概要

論文の詳細を見る
Fracture toughness (K_<lc>) of structural ceramics such as alumina, silicon nitride, silicon carbide was evaluated using a single edge precracked beam (SEPB) technique. An indentation crack or a sawed notch was introduced into the specimen as an origin for sharp precrack, followed by developing an atomically sharp pop-in crack from the crack or notch. The sharply pre-cracked specimens were fractured by 3-point bending under a cross-head speed of 0.5 mm/min at room temperature. The K_<lc> values obtained from each measurement showed a good reproducibility for alumina and silicon carbide. For silicon nitride, however, the values scattered a little, especially when a sharp pop- in crack was introduced from the indentation crack. The causes of the scattering were discussed on based the observation of inclined precrack front and deflected fracture surface.
1988-05-01