scholarly journals Research on Dynamic and Mechanical Properties of Magnetoactive Elastomers with High Permeability Magnetic Filling Agent at Complex Magneto-Temperature Exposure

Author(s):  
Maria Vasilyeva ◽  
Dmitry Nagornov ◽  
Grigory Orlov

The paper describes the research findings on dynamic and mechanical properties of composite elastomers with high permeability magnetic filling agent capable of rapidly and reversibly changing its properties when exposed to an external magnetic field, which makes it a perspective material for application in a wide range of engineering areas. The research has analyzed the trends in the strength properties of the materials obtained through the use of filling agents of different fineness, content, and structural organization in the final polymer, under different conditions. This allowed to obtain the correlations between the influence of the filler's relative fineness on the dynamic and mechanical properties of composite polymers, and to estimate the trends in the parameters describing the material strength under the complex magnetic and thermal influence. The results obtained by the authors allowed to ground the composition and structural organization of the final material with the best set of dynamic and mechanical properties.

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2376
Author(s):  
Maria Vasilyeva ◽  
Dmitriy Nagornov ◽  
Georgiy Orlov

We consider magnetically active elastomer as a potentially applicable material for manufacturing a working channel of a magnetic pump unit. During the study, the samples were exposed to a magnetic field, a temperature field, and their combination to assess the change in the elastic-strength properties of the final material. For the preparation of samples, high permeability magnetic fillers of various sizes were used in the concentration range of 50–70%. Samples were made with an isotropic and an anisotropic structure. Studies have shown that when using a filler with a relatively coarse fraction, the material has more stable dynamic and mechanical characteristics: the tensile strength of the sample increases by an average of 38%. With the combined effect of magnetic and temperature fields on the material, its elasticity and strength increase by an average of 30% in comparison with the material without external influence. Based on the results obtained, the composition and structural organization of the material, which has the best complex of elastic strength characteristics, has been substantiated. For the manufacture of a pumping unit tube, it is preferable to use an isotropic magnetoactive elastomer with a coarser filler content of about 60%.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.


2018 ◽  
Vol 935 ◽  
pp. 79-83
Author(s):  
A.N. Volotskoy ◽  
Yuriy V. Yurkin ◽  
V.V. Avdonin

This research is devoted to the actual problem of the development of damping polymer materials which are effective in a wide range of temperatures and having satisfactory strength characteristics. There are many works devoted to the study of dynamic mechanical properties of filled composites, but most do not take into account the influence of plasticizer on the strength properties of the polymer, as they change its characteristics for the worse. In this respect, the study and comparison of the mechanical properties of the polymer base with the introduction of different types and concentrations of plasticizers is an urgent task. According to the received regularities it was possible to define the type, concentration and boundaries of the polarity of the plasticizer, which reduces the strength characteristics of ethylene-vinyl acetate to a lesser degree.


MRS Bulletin ◽  
1986 ◽  
Vol 11 (5) ◽  
pp. 15-21 ◽  
Author(s):  
W. C. Oliver

A mechanical properties microprobe is an exciting concept. A system with the ability to evaluate the mechanical response of a sample with submicron spacial resolution would have an extremely wide range of applications. Recent developments in hardware and understanding have placed this goal within our grasp.In 1971, J.J.Gilman wrote the following in his article, “Hardness—A Strength Microprobe”:“Hardness measurements are at once among the most maligned and the most magnificent of physical measurements. Maligned because they are often misinterpreted by the uninitiated, and magnificent because they are so efficient in generating information for the skilled practitioner. They can quickly yield quantitative information about the elastic, anelastic, plastic, viscous, and fracture properties of a great variety of both isotropic and anisotropic solids. The tools that are used are simple and the sample sizes that are needed are typically small, sometimes submicroscopic. This makes it unnecessary to have large specimens in order to measure strength properties and makes it possible to measure the properties of various microscopic particles within the matrix phase of a polyphase metal, mineral, or ceramic material. This is why hardness may be considered to be a strength microprobe.”These statements are worth repeating for two reasons. First, they point out the largely untapped potential for microin-dentation tests to improve our understanding of the mechanical properties of materials. Second, it is the first mention of hardness tests in the context of a strength microprobe. In this article the more general term of microindentation tests will be used, since hardness is only one of many properties that can be measured with such tests. In addition, the term mechanical properties microprobe (MPM) will be used rather than strength microprobe-again, to note the wide variety of properties that can be measured.


2016 ◽  
Vol 18 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Małgorzata Szymiczek ◽  
Maciej Rojek ◽  
Gabriel Wróbel

Abstract Drawing up diagnostic relations between thermal characteristics determined in thermal imaging examinations and mechanical properties, allowing for forecasting the state of material during the use, was a purpose of the work. Research was performed on polyester – glass composites which were subjected to the ageing-fatigue degradation process in a device created specifically for that purpose. It was indicated how to assess the degree of the decline, taking into account the fall in material strength properties. The basis of a method was measurement of changes in temperature in activated thermal processes. Relations between changes of the speed of heating and cooling were related to the bending strength and the modulus of elasticity. Diagnoses were backed up with microscopic examinations.


2017 ◽  
Vol 17 (4) ◽  
pp. 137-142 ◽  
Author(s):  
S. Pysz ◽  
R. Żuczek ◽  
J. Piekło ◽  
M. Maj

Abstract The ecological meanings clearly indicates the need of reducing of the concentration of the CO2 in the atmosphere, which can be accomplished through the lowering of the fuel consumption. This fact implies the research for the new construction solutions regarding the reduction of the weight of vehicles. The reduced weight of the vehicle is also important in the case of application of the alternative propulsion, to extend the lifetime of the batteries with the reduction of recharge cycles. The use of cast alloy AlZnMgCu compliant of plastic forming class 7xxx alloy, are intended to significantly reduce the weight of the structures, while ensuring high strength properties. The wide range of the solidification temperature, which is more than 150°C, characterizes this alloy with a high tendency to create the micro and macro porosity. The study presents the relationship between the cooling rate and the area of occurrence and percentage of microporosity. Then the results were linked to the local tensile strength predicted in the simulation analysis. The evaluation of the microporosity was performed on the basis of the CT (computed tomography) and the analysis of the alloy microstructure. The microstructure analysis was carried out on test specimen obtained from the varying wall thickness of the experimental casting. The evaluation of the mechanical properties was prepared on the basis of the static tensile test and the modified low cycle fatigue test (MLCF).


2019 ◽  
Vol 16 (32) ◽  
pp. 139-146
Author(s):  
Vadim P ZAKHAROV ◽  
Aigiz G KHUSNULLIN ◽  
Elena M ZAKHAROVA ◽  
Anzhela S SHURSHINA ◽  
Elena I KULISH

It was investigated the effect of the method of obtaining polymer composites based on the blend of polymers over a wide range of their ratios on the rheological and physical-mechanical properties. The composites were prepared (using pressing or pressure die casting) on the basis of secondary polypropylene (PP) and the following polymers: 1) ultra high molecular polyethylene (UHMPE); 2) ethylene propylene diene monomer (EPDM); 3) secondary low pressure polyethylene (LPPE). Pressing was carried out on an automatic hydraulic press "AutoMH-NE" (Carver, the USA) at 210°C and endurance under pressure of 7000 kgfs within 3 min. Injection molding was performed using a Babyplast automatic molding machine of the horizontal type with an injection volume of up to 15 cm3. In both cases, the compositions also went through a stage of the preliminary mixture at the laboratory station (plastograf) of "PlastographEC" (Brabender, Germany) within 15 min at a load of 200 N. Estimation of rheological properties of the polymer composition melts was performed using a Haake Mars III rheometer. The deformation-strength properties were studied according to the State Standard GOST 11262-80 with a tensile testing machine "Shimadzu AGS-X". Using the data of relative rheometry, it is determined for all the systems studied (blends PP with UHMPE, EPDM, and LPPE) that variation of the maximum torque with composite composition is non-additive. This seems to be due to the occurring phase reversal. The present fact finds its support when performing rheological investigations using absolute rheometry. It is shown that variations in the phase structure of composites occurring in the phase reversal area lead to the corresponding changes in the deformation-strength properties of composites.


Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.


2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.


2020 ◽  
pp. 313-317
Author(s):  
A.I. Kovtunov ◽  
Yu.Yu. Khokhlov ◽  
S.V. Myamin

Titanium—aluminum, titanium—foam aluminum composites and bimetals obtained by liquid-phase methods, are increasingly used in industry. At the liquid-phase methods as result of the reaction diffusion of titanium and aluminum is formed transitional intermetallic layer at the phase boundary of the composite, which reduces the mechanical properties of titanium and composite. To reduce the growth rate of the intermetallic layer between the layers of the composite and increase its mechanical properties, it is proposed to alloy aluminum melt with nickel. The studies of the interaction of titanium and molten aluminum alloyed with nickel made it possible to establish the effect of temperature and aluminizing time on the thickness, chemical and phase compositions of the transition intermetallic layer. The tests showed the effect of the temperature of the aluminum melt, the nickel concentration on the strength properties of titanium—aluminum bimetal.


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