PSI - Issue 13

Alexey Evstifeev et al. / Procedia Structural Integrity 13 (2018) 886–889 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

889

4

2024 ASTM 5556 ASTM 1230 ASTM

66 68 70 72 74 76 78 80 82 84 86 88 90 92

S, %

0,1

1

10

100

1000

Strain rate, 1/s Fig. 3. The percentage of the viscous fracture component S (in %) for aluminum alloys: circle – 1230, square – 5556, triangle - 2024.

Conclusion Determination of the strength characteristics is necessary in the development and implementation of engineering materials. For aluminum alloys, this can be achieved by applying severe plastic deformation. At present this direction has not been sufficiently studied from the point of view of improving the dynamic properties of materials. The experiments were carried out on a pure aluminum alloy and alloys of Al-Mg and Al-Cu-Mg systems, Strength properties of aluminum alloys were determined in the different loading conditions. The correlation between the ultimate strength and strain rate was observed under quasi static and dynamic loads. For each alloy, a nonlinear relationship was observed between the threshold characteristics of external loads and the ability of materials This effect was explained using structural time fracture criteria. For each alloy, the parameters of the materials were determined, which characterize them under quasi static and dynamic loading. The greatest strength of materials from the point of view of incubation time is pure aluminum. But in quasi static operating conditions, the alloys 5556 and 2024 are the most durable. Existence of alloying elements in aluminum alloys led to decrease in ductility and increase strength. Microstructure investigations also confirm that the destruction of alloys 2024 and 5556 under dynamic tension loading becomes more brittle than for the original alloy. Acknowledgements The work has been done under financial support from the Russian Science Foundation (№17 -79-10145). Experimental research were performed at the Research parks of St.Petersburg State University «The study of extreme states of materials and constructions» and «Centre for X-ray Diffraction Studies». References Valiev, R. Z., 1996. Ultrafine-grained materials produced by severe plastic deformation: an introduction. In Annales de Chimie, Science des Materiaux(France), 21(6), 369-378. Valiev, R. Z., Korznikov, A. V., Mulyukov, R. R., 1993. Structure and properties of ultrafine-grained materials produced by severe plastic deformation. Materials Science and Engineering: A, 168(2), 141-148. Sabirov, I., Murashkin, M. Y., Valiev, R. Z., 2013. Nanostructured aluminium alloys produced by severe plastic deformation: New horizons in development. Materials science and engineering: A, 560, 1-24. Evstifeev, A.D., 2018, Investigation of strength characteristics of aluminum alloy under dynamic tension. J. Phys.: Conf. Ser. 991, 012019. Petrov, Y.V., Utkin, A.A., 1989. On the Dependence of Dynamic Strength on Loading Rate. Sov. Mater. Sci. 25(2), 153-156. Petrov, Y.V., Morozov N.F., 1994. On the Modeling of Fracture of Brittle Solids. ASME J. Appl. Mech. 61, 710-712. Petrov, Y., Bragov, A., Evstifeev, A., Cadoni E., 2015. Structural-temporal approach for dynamic strength characterization of gabbro-diabase. EPJ Web of Conferences. 94, Article number 01042. Petrov, Y., Smirnov, I., Evstifeev, A., Selyutina, N., 2013. Temporal peculiarities of brittle fracture of rocks and concrete. Frattura ed Integrit`a Strutturale 24, 112 – 118.