PSI - Issue 18

Sergey Uvarov et al. / Procedia Structural Integrity 18 (2019) 309–313 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Specific energy, released at this peak is 0.039J/g for 15% strain, 0.525J/g for 30% and 0.271J/g for 50%. The specific stored energy amount increases with the number of serrations except the final stage of the load prior to the failure. The fact that the specific stored energy is decreasing before failure is in consistency with the idea that this stored energy is released during collective structural relaxation leading to appearance of cracks and failure. And the second critical point in the D’Anna paper can be related to the damage to failure transition. Multiple cracking found on the surface of the specimen (fig 5) supports this finding.

Fig. 5. SEM image of the cracks on the surface of the specimen loaded to 50% strain.

Acknowledgements This work was carried out with partial support of the RFBR grants 17-08-00905_a, 17-41-590149 p_a, References D’Anna, G., Nori, F., 2000. Critical Dynamics of Burst Instabilities in the Portevin-Le Châtelier Effect. Physical Review Letters 85, 4096–4099. https://doi.org/10.1103/PhysRevLett.85.4096 Naimark, O.B., 2016. Some regularities of scaling in plasticity, fracture, and turbulence. Physical Mesomechanics 19, 307–318. https://doi.org/10.1134/S1029959916030097 Marchand, A., Duffy, J., 1988. An experimental study of the formation process of adiabatic shear bands in a structural steel. Journal of the Mechanics and Physics of Solids 36, 251–283. https://doi.org/10.1016/0022-5096(88)90012-9 Froustey, C., Panteleev, I., Lyapunova, E., Naimarkb, O., 2016. Defect induced shear instability and ASB failure in metals. Procedia Structural Integrity, 21st European Conference on Fracture, ECF21, 20-24 June 2016, Catania, Italy 2, 1959–1966. https://doi.org/10.1016/j.prostr.2016.06.246 Dierke, H., Krawehl, F., Graff, S., Forest, S., Šachl, J., Neuhäuser, H., 2007. Portevin–LeChatelier effect in Al–Mg alloys: Influence of obstacles – experiments and modelling. Computational Materials Science 39, 106–112. https://doi.org/10.1016/j.commatsci.2006.03.019 Chihab, K, Estrin, Y. Kubin, L.P. Vergnol, J. Scripta Metall. 21 (1987) 203–208.