Prediction of anisotropic LCF behavior for SLM Ti-6Al-4V considering the spatial orientation of defects
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作者
Hu, Dianyin; Pan, Jinchao; Mi, Dong; Mao, Jianxing; Li, Wei; Fu, Yanan; Wang, Rongqiao
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刊物名称
INTERNATIONAL JOURNAL OF FATIGUE
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年、卷、文献号
2022, 158, 0142-1123
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关键词
Hu, Dianyin; Pan, Jinchao; Mi, Dong; Mao, Jianxing; Li, Wei; Fu, Yanan; Wang, Rongqiao
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摘要
The inevitable defects in additive manufacturing (AM) materials reduce their low cycle fatigue (LCF) lifetime. Here a method for correlating defect size and spatial orientation with building direction is presented to evaluate the anisotropy characteristic of AM materials fatigue resistance. An ellipsoidal equivalent criterion is developed based on the principal component analysis method to capture the common features of the defect population which is obtained by synchrotron radiation X-ray tomography. The size characteristics are correlated with the spatial orientation characteristics of defects by using the polar figure. Then, based on the micro-plasticity zone theory, an effective driving stress for defect-induced failure is proposed. A lifetime model is further developed based on the effective stress, and its capability in anisotropic fatigue lifetime prediction is verified by performing LCF tests on the specimens with different building directions.
