On the deformation behavior of bi-metal via digital image correlation

The aim of this contribution was to study the localization of the plastic deformation of bi-metal based on a low-carbon steel A 283 Grade C and austenitic stainless steel 301 AISI. The images of the localized zone plastic deformation upon the uniaxial tension have been obtained with using digital image correlation method (DIC). The stress-strain curves are found to show all the plastic flow stages: yield plateau, linear and parabolic work hardening stages and the prefracture stage would occur for the respective values of the exponent from the Ludwik-Holomon equation. The main parameters of plastic flow localization at various stages of the deformation hardening have been determined in bi-metal

On slow wave process in rocks

A study was made of the general regularities of localized plasticity development in deforming rocks. The potential usefulness of speckle photography techniques in applications to problems of deformation and fracture in rocks was explored and circumscribed. The evolution of localized plasticity in rocks was addressed using wave ideas. The tests were performed for the compression samples of marble, silvinite and sandstone; the deformation occurred in these materials via different micromechanisms of plasticity. By the deformation, autowaves would form in the compression samples of rocks. The autowave propagation rates are in the range ~10−5...10−4 m/s (0.3...3 km/yr), which is close to slow motion rates observed in the earth crust after an earthquake or a rockslide. A correlation has been established between the calculated and experimental data on the time and coordinates of fracture in rocks

Microstructure of superconducting cable components

Using atomic force, optical and electron microscopy methods, the changes in the microstructure and phase composition were investigated for the alloy Nb47%Ti used for the manufacture of superconducting cable employed as current-carrying elements in the magnetic system for International Thermonuclear Experimental Reactor. The test samples were prepared from the superconducting wire at an intermediate step of the drawing process for the area reduction Ø1.3→Ø1.2 mm. The effect of cold drawing and intermediate annealing on the properties of as-worked Nb-Ti alloy was assessed. Local strain zones were found to occur in the rupture area. The shape and chemical composition of Nb-Ti wire was examined for both a defect-free area and the rupture area. A Nb diffusion barrier was found to occur in the copper matrix of Nb-Ti wire

Ultrasound velocity measurements in high-chromium steel under plastic deformation

In the present study, the variation of the propagation velocity of ultrasound in the plastic deformation of corrosion-resistant high-chromium steel 40X13 with ferrite-carbide (delivery status), martensitic (quenched) and sorbitol (after high-temperature tempering) structures have beem studied/ It is found that each state shows its view of the loading curve. In the delivery state diagram loading is substantially parabolic throughout, while in the martensitic state contains only linear strain hardening step and in the sorbitol state the plastic flow curve is three-step. The velocity of ultrasonic surface waves (Rayleigh waves) was measured simultaneously with the registration of the loading curve in the investigated steel in tension. It is shown that the dependence of the velocity of ultrasound in active loading is determined by the law of plastic flow, that is, the staging of the corresponding diagram of loading. Structural state of the investigated steel is not only changing the type of the deformation curve under uniaxial tension, but also changes the nature of ultrasound speed of deformation

The effect of hydrogen embrittlement on the mechanical properties of aluminum alloy

The effect of hydrogen embrittlement on the mechanical properties of aluminum alloy D1 was investigated. The studies were performed for the test samples of aluminum alloy subjected to electrolytic hydrogenation. It is found that the mechanical properties of aluminum alloy are affected adversely by hydrogen embrittlement. The hydrogenated counterpart of alloy has a lower degree of ductility relative to the original alloy; however, the plastic flow behavior of material remains virtually unaffected. The deformation diagrams were examined for the deformed samples of aluminum alloy. These are found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Ludwik-Holomon equation. Microhardness tests were performed for as-treated aluminum alloy D1; the measurement results are presented

Heterogeneity of plastic flow of bimetals electrolytically saturated with hydrogen

This paper presents the study of a corrosion-resistant bimetal composed of austenitic stainless steel (301 AISI) and low-carbon construction steel (A 283 Grade C) and the effect of its electrolytic hydrogenation on plastic flow of the test material. Localization patterns of plastic deformation in the process of uniaxial tension were obtained using the digital image correlation method. The evolution of localized plastic deformation zones was studied in the initial state and after electrolytic hydrogenation. The staging of stress-strain curves was analyzed