PSI - Issue 28

Ping Zhang et al. / Procedia Structural Integrity 28 (2020) 1176–1183 P. Zhang et al. / Structural Integrity Procedia 00 (2019) 000–000

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whereas the [001] specimen at 24 °C shows almost a linear path due to its single direction path (Fig. 3) and the 650 °C [001] has a step change at around 12 cycles. We also notice that cracks initiate faster in our simulations compared to the experiments. This is due to the predefined crack, which introduced extra stress concentration around the crack tip. Meanwhile, the overall trends of numerical crack growth are consistent with experiments, especially in the crack length region of 40 μm to 110 μm. 5. Conclusions This study combined the crystal plasticity and XFEM to evaluate the short crack propagation in a Ni-based single crystal superalloy of [001] and [111] orientation at 24 °C and 650 °C. The cumulative shear strain was adopted as a damage criterion to describe the crack growth along crystallographic directions. The experimentally observed tortuous crack paths and irregular propagation rate were captured and details of crack deflections were further explained by analysing the evolution of slip plane activity. In conclusion, this research provides an approach to study the evolution mechanism of short crack propagation. Acknowledgements P. Zhang would like to acknowledge the support from the China Scholarship Council (CSC, No. 201806290092). The work was also funded by the EPSRC (Grant EP/M000966/1 and EP/K026844/1) of the UK. References Carroll, J.D., Abuzaid, W., Lambros, J., Sehitoglu, H. 2013. High resolution digital image correlation measurements of strain accumulation in fatigue crack growth. International Journal of Fatigue, 57, 140–150 Huang, Y. 1991. A User-Material Subroutine Incorporating Single Crystal Plasticity in the ABAQUS Finite Element Program. Mech report 178, 1991 Lin, B., Zhao, L.G., Tong, J. 2011. A crystal plasticity study of cyclic constitutive behaviour, crack-tip deformation and crack-growth path for a polycrystalline nickel-based superalloy. Engineering Fracture Mechanics, 78, 2174–2192 Ma, X., Shi, H., Gu, J., Wang, Z., Harders, H., Malow, T. 2008. Temperature effect on low-cycle fatigue behavior of nickel-based single crystalline superalloy. Acta Mechanica Solida Sinica, 21, 289–297 MacLachlan, D.W., Wright, L.W., Gunturi, S., Knowles, D.M. 2001. Constitutive modelling of anisotropic creep deformation in single crystal blade alloys SRR99 and CMSX-4. International Journal of Plasticity, 17, 441–467 Moës, N., Dolbow, J., Belytschko, T. 1999. A finite element method for crack growth without remeshing. International Journal for Numerical Methods in Engineering, 46, 131–150 Peirce, D., Asaro, R.J., Needleman, A. 1982. An analysis of nonuniform and localized deformation in ductile single crystals. Acta Metallurgica, 30, 1087–1119 Wilson, D., Wan, W., Dunne, F.P.E. 2019. Microstructurally-sensitive fatigue crack growth in HCP, BCC and FCC polycrystals. Journal of the Mechanics and Physics of Solids, 126, 204–225 Zhang, L., Zhao, L.G., Roy, A., Silberschmidt, V.V.V., McColvin, G. 2019. In-situ SEM study of slip-controlled short-crack growth in single crystal nickel superalloy. Materials Science and Engineering: A, 742, 564–572 Zhang, P., Zhang, L., Baxevanakis, K.P., Zhao, L.G., Bullough, C. 2020. Modelling short crack propagation in a single crystal nickel-based superalloy using crystal plasticity and XFEM. International Journal of Fatigue, 136, 105594 Zhao, L.G., Tong, J. 2008. A viscoplastic study of crack-tip deformation and crack growth in a nickel-based superalloy at elevated temperature. Journal of the Mechanics and Physics of Solids, 56, 3363–3378