Swedish Energy Agency と Siemens Industrial Turbomachinery ABの協力のもと行われた単結晶ニッケル合金を対象とした研究事例。 ガスタービンの高温部で頻繁に使用される単結晶ニッケル合金の、結晶き裂前縁でのResolved Stress Intensity Factor (RSIF)、結晶き裂伝播速度を算出。確認されたき裂伝播速度は、結晶き裂前縁と良い相関関係を示している。

資料より抜粋(本Web向けに図番号を変更)：
The equivalent RSIF was then calculated along the crack fronts where crystallographic cracking is present and the conventional anisotropic SIFs are calculated for the parts of Mode I cracking. This is done for the cracks corresponding to the heat tints, since the crack geometry can be approximated best. The anisotropic SIFs are calculated by the crack evaluation tool FRANC3D.The FE-solver of ABAQUS is used to calculate the displacements. The results are shown Fig. 2, where it can be seen that all data points for both crystallographic cracks fall into a narrow band. The blue squares correspond to the left and the orange squares to the right crystallographic crack front.



Fig1. Heat tints on fracture surface of specimen Kb1. Cracks instances 0, 1 and 2 are high lighted in blue, green and red, respectively.



Fig2. Crystallographic crack propagation rate

参照：Busse,C., Palmert,F., Wawrzynek,P., Sjodin,B., Gustafsson,D. and Leidermark,D. (2019) Crystallographic crack propagation rate in single-crystal nickelbase superalloys. MATEC Web of Conferences 165, 13012 FATIGUE 2019