Ural Federal University named after the first President of Russia B. N. Yeltsin, Ekaterinburg, Russia:

Yu. N. Loginov, Professor (Institute of Material Science and Metallurgy)

LLC “Ekaterinburg Non-Ferrous Metals Processing Plant – Engineering”, Verkhnyaya Pyshma, Russia:
A. A. Fomin, Mechanical Engineer, e-mail: a.fomin@ezocm.ru

The aim of this work was to obtain new data about the rheological properties of alloy Pt81Pd15Rh3.5Ru0.5, used for applications in catalytic systems for the chemical industry. The wire tensile test on Instron – 3365 testing machine was used as a basic test method. The study was performed in the mechanical testing laboratory (Ekaterinburg Non-Ferrous Metals Processing Plant), and the processing routes of this company were used for subsequent drawing. The alloy has a low level of plastic properties, and it is desirable to describe the deformation resistance in a wide range of deformations. Therefore, the study was divided in two stages. At the first stage the diagram of loading, recorded by the specialized software Bluehill Lite, was processed, and dependence between the true stresses and deformations was defined. It allowed obtaining of information in the range of relative elongations preceding the beginning of the necking, i.e. until the end of the uniaxial loading mode. The annealed wire samples with diameter of 1.21 mm and working length of 100 mm (annealing in air for 30 min at the temperature of 1000 ^оC) were used for the first stage of tests. The speed of movement of the testing machine grips was 50 mm/min, which corresponds to a deformation rate of 0.008 1/s at the beginning of the test and 0.010 1/s at the moment of the sample rupture. The hardening curve for deformation of not more than 12% was obtained during the first stage. The second stage of the study was based on the definition of conditional yield strength as the stress of the metal transferring from a state of elasticity in a state of plasticity in the scheme of uniaxial loading, as the concept of deformation resistance. During the tests, the diameter was reduced by wire drawing with sampling on the diameters of 1.21 – 0.99 – 0.82 – 0.67 – 0.51 mm, with deformation degree values of 0, 0.401, 0.778, 1.182, 1.728, which corresponds to the relative elongations of 0, 33, 54, 69, 82 %, respectively. The practical value of the obtained results is the possibility of using the received dependencies in the form of graphs and approximated data for formulation and solution of particular boundary problems of metal forming (for example, by the finite element method).
This work was carried out with the financial support of the Decree of the Government of Russian Federation No. 211, Agreement No. 02.А03.21.0006.

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