ガス圧焼結窒化けい素のき裂進展および強度の破壊力学的評価

概要

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Crack growth behavior was investigated under static and cyclic loads in gas-pressure-sintered silicon nitride (EC-141) using a combined loading technique for stabilizing crack growth and a surface film technique for monitoring crack length. Load shedding tests were performed on two speciments at the loading frequencies of 1 and 10 Hz to evaluate fatigue crack growth until the crack became dormant, in order to determine the threshold stress intensity factor K_<th>. Then, one of the specimens was used in a fatigue test without the combined loading technique, in which K_<th> values for different crack lengths were determined. The other specimen was used in the quasi-static test under a monotonic loading condition, in which the fracture resistance curve for the fatigue precrack was measured. The results were compared to those reported in the literature for the same material and for other silicon nitrides. Based on the crack growth characteristics, the fracture strength under various loading conditions involving static, cyclic and monotonic loads was discussed.
一般社団法人日本機械学会の論文
1993-07-25