シェブロン切欠き試験片によるセラミックスの破壊じん性評価

概要

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Chevron-notched specimens are being used reentry to determine K_<Ic>. In this study,the stress intensity factors were calculated for chevron-notched three point bend and compact specimens. Three configuration of chevron-notched specimens were then subjected to fracture toughness tests to determine K_<Ic> of hot-pressed silicon nitride, Si_3N_4, with special attention paied to the fracture resistance curve (R-curve). Using this result, the optimum shape of the specimen was determined. The results obtained are summarized as follows. (1) By using the deeply chevron-notched specimen, K_<Ic> can be determined in a simple way with little scatter. (2) The K_<Ic> values determined by using the straight-notched specimens show a considerable scatter due to the effect of finite notch root radius and they overestimate the actual K_<Ic> value. (3) From the change in specimen compliance, the R-curve can be evaluated. The resistance to stable crack growth increases slightly as the crack grows.
社団法人日本材料学会の論文
1986-08-15