PSI - Issue 46

W. Li et al. / Procedia Structural Integrity 46 (2023) 119–124 Wei Li et al. / Structural Integrity Procedia 00 (2021) 000–000

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Fig. 3. Interior cracking mechanism at elevated temperature: (a) Intensified slip lines or bands and oxide layer thickening; (b) Nucleation of microcrack; (c) Formation of facets and crack deflection; (d) Formation of CDA and subsequent long crack growth. 4. Conclusions (1) The crystallographic facets induced cracking of SLM Ni-based superalloy has been a predominant failure mode in the long life regime at elevated temperature. (2) Due to the inhibition effect of oxidate layer, the interior crack nucleation is promoted and heavily related to the accelerated dislocation movement and slipping within the interior grains that are located in the highest shear stress plane, especially with the presence of twin boundaries and metallurgical defects. (3) The grain orientation difference leads to the rough crack morphology with an obvious deflection phenomenon within the CDA. Moreover, the formation of CDA marks the beginning of long interior crack propagation. Acknowledgements This work was supported by the National Natural Science Foundation of China (grant numbers 51775043, 52175128, U1864210). References Balachandramurthi, A.R., Moverare, J., Dixit, N., Pederson, R., 2018. Influence of defects and as-built surface roughness on fatigue properties of additively manufactured alloy 718, Mater. Sci. Eng. A 735, 463–474. Balokhonov, R., Romanova, V., Kulkov, A., 2020. Microstructure-based analysis of deformation and fracture in metal-matrix composite materials. Engineering Failure Analysis, 110(10), 104412. Božić, Ž., Schmauder, S., Wolf, H., 2018. The Effect of Residual Stresses on Fatigue Crack Propagation in Welded Stiffened Panels. Engineering Failure Analysis 84, 346–357. Božić, Ž., Schmauder, S., Mlikota, M., Hummel, M., 2014. Multiscale Fatigue Crack Growth Modelling for Welded Stiffened Panels. Fatigue and Fracture of Engineering Materials and Structures 37(9), 1043–1054. Cheloee Darabi, A., Kadkhodapou,r J., Pourkamali Anaraki, A., Khoshbin, M., Alaie, A., Schmauder, S., 2021. Micromechanical modeling of damage mechanisms in dual-phase steel under different stress states, Engineering Fracture Mechanics 243, 107520. Cooke, S., Ahmadi, K., Willerth, S., Herring, R., 2020. Metal additive manufacturing: Technology, metallurgy and modelling, J. Manuf. Process. 57, 978–1003.