PSI - Issue 28

Konstantinos Tserpes et al. / Procedia Structural Integrity 28 (2020) 1644–1649 Tserpes, Bazios, Pantelakis, Michailidis / Structural Integrity Procedia 00 (2019) 000–000

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(a) (b) Fig. 5. Comparison of the numerical and experimental load-depth curves for (a) the cW-Cu alloy and (b) the W-Cu alloy. In the model, a sharp and a rounded tip were considered for the Berkovich indenter. 6. Conclusion In the present wok, the nanoindentation performance of two Tungsten – Copper nanocrystalline alloys, a coarse grained alloy and a nanostructured alloy, was studied experimentally and numerically. The experimental results have revealed a higher nanoindentation resistance and higher mechanical properties of the nanostructured alloy, which is explained by the Hall-Petch effect. It is important to note that for the nanostructured alloy an extraordinary yield strength of the order of 3.0 GPa was derived. The model was proved capable to simulate the nanoindentation performance of the two alloys and has demonstrated the effect of sharpness of the Berkovich tip. Acknowledgements A part of the work described in the paper has received funding from the European Union's Horizon 2020-FETOPEN research and innovation programme under Grant Agreement no. 713514: ICARUS project (Innovative Coarsening resistant Alloys with enhanced Radiation tolerance and Ultrafine-grained Structure for aerospace application). References Bazios, P., Tserpes, K. and Pantelakis, S., 2020. Modelling and Experimental Validation of the Porosity Effect on the Behaviour of Nano-Crystalline Materials. Metals , 10(6), p.821. Bazios, P., Tserpes, K. and Pantelakis, S., 2019. Numerical Computation of Material Properties of Nanocrystalline Materials Utilizing Three Dimensional Voronoi Models. Metals , 9(2), p.202. Bolshakov, A., Oliver, W. and Pharr, G., 1996. Influences of stress on the measurement of mechanical properties using nanoindentation: Part II. Finite element simulations. Journal of Materials Research , 11(3), pp.760-768. Bouzakis, K., Michailidis, N., Hadjiyiannis, S., Skordaris, G. and Erkens, G., 2002. The effect of specimen roughness and indenter tip geometry on the determination accuracy of thin hard coatings stress–strain laws by nanoindentation. Materials Characterization , 49(2), pp.149-156. Cavaliere, P., 2009. Mechanical properties of nanocrystalline metals and alloys studied via multi-step nanoindentation and finite element calculations. Materials Science and Engineering: A , 512(1-2), pp.1-9. Cavaliere, P., 2007. Strain Rate Sensitivity and Fatigue Properties of an Al-fe Nanocrystalline Alloy Produced by Cryogenic Ball Milling. Multidiscipline Modeling in Materials and Structures , 3(2), pp.225-234. Cheng, Y. and Cheng, C., 1998. Relationships between hardness, elastic modulus, and the work of indentation. Applied Physics Letters , 73(5), pp.614-616. Dao, M., Chollacoop, N., Van Vliet, K., Venkatesh, T. and Suresh, S., 2001. Computational modeling of the forward and reverse problems in instrumented sharp indentation. Acta Materialia , 49(19), pp.3899-3918. Doerner, M. and Nix, W., 1986. A method for interpreting the data from depth-sensing indentation instruments. Journal of Materials Research , 1(4), pp.601-609. Fougere, G., Riester, L., Ferber, M., Weertman, J. and Siegel, R., 1995. Young's modulus of nanocrystalline Fe measured by nanoindentation. Materials Science and Engineering: A , 204(1-2), pp.1-6. Gram, M., Carpenter, J. and Anderson, P., 2015. An indentation-based method to determine constituent strengths within nanolayered composites. Acta Materialia , 92, pp.255-264. Han, F., Tang, B., Kou, H., Li, J. and Feng, Y., 2020. Experiments and Crystal Plasticity Finite Element Simulations Of Nanoindentation On Ti– 6Al–4V Alloy.