Key Engineering Materials Vol. 743

Abstract: Currently, the use of technogenic raw materials, including wood waste is one of the trends in manufacturing of building materials. This is due to the limited resources, the need for long-distance transportation, the high material and energy cost of some technological processes of raw materials extraction and processing. All of them greatly hamper the development of the industry of building materials based on natural resources. Different cellulosic fillers of vegetable origin are used for the production of wood-cement compositions at the moment. Organic fillers along with the inherent valuable properties have a number of specific properties which have a significant effect on the processes of structure formation, structural-mechanical and construction properties of composites. The results of the research of the processes of water-soluble components removal from raw wood material are presented in the article. Processing of raw wood material was carried out in water and weak alkali solution in the research process. It is established that additional ultrasonic treatment considerably intensifies and increases the extraction of water-soluble sugars. The conducted research shows the possibility of improving the composite wood materials manufacturing technology with the aim of improving their performance without significant capital investments.

Abstract: A mechanism for the formation of the interaction zone at the interlayer interface of the explosively welded Cu-Ti system composite is proposed and experimentally proved; the heat treatment was performed under a contact melting regime.

Abstract: This paper studies the influence of work conditions, difference compression load and counterface roughness, on UHMWPE under abrasive wear test without lubrication according to GOST 426-77. It was found that the formation of deep and wide furrows on worn surface and abrasive intensity increased when the number of grit grade was decreased (average grit size increase). The behavior of abrasive wear can be classified as follows: the first characteristic volume loss quickly increases in the beginning of running time about 5-15 minutes, which is referred to as “run-in” wearing stage; the second characteristic volume loss regularly increases after running time about 15 minutes, which is approaching to “steady-state” wearing stage. In addition, the abrasive wear intensity increase with increasing compression load and/or decreasing number of grit grade (average grit size increase). The results of this research can be applied to abrasive applications in mechanical engineering.

Abstract: The paper presents the results of defectiveness study of high-strength lightweight concrete. It was shown that the three stages of the acoustic emission energy kinetics with different intensity and duration characterize the processes of defect formation. It was found that the introduction of hollow ceramic microspheres into fine-grained sand concrete to a certain extent provides the formation of the concrete structure with a longer "safety zone" (i.e. the stage when the load increase does not lead to a substantial increase in acoustic emission energy and strains). It was found that the reduction of the structural defects of high-strength lightweight concrete with high content of hollow microspheres is possible by the use of nanomodifier at the phase boundary. It was shown that the greater effect is achieved for nanomodified high-strength lightweight concrete with average density of 1300-1500 kg/m³.

Abstract: The article describes a technology for producing carbon-graphite-aluminium composite by non-autoclave gasless impregnation of a carbon-graphite skeleton by matrix alloy of aluminium and presents the results of testing, application areas and assessment of the properties of obtained composites as well.

Abstract: The electrical properties of anisotropic materials based on microwires in extremely high frequency (EHF) range were researched. The frequency dependence of the transmission coefficient of electromagnetic wave for materials based on FeCoBSi microwires in parallel and orthogonal ordering of conductors relative to the polarization of incident radiation are shown. Angular dependence of the transmission coefficient for these samples at different of frequencies are presented. It was shown, that samples of ordered structure based on microwires with a repetition period 1 mm provides changing transmission coefficient from 35% to 60% in the range of 38-56 GHz.

Abstract: The research of quasi-breather statistical characteristics in the model crystal of A₃B stoichiometry is conducted by means of molecular dynamics method in the paper by the example of Pt₃Al. The phonon spectrum of this model crystal, the dependences of mean-square deviation, the coefficient of variation and the average frequency of the model quasi-breather on the time of its existence are obtained. The statistical data analysis allows for the conclusion that a quasi-breather model solution slightly differs from the exact breather corresponding to it in the model under consideration using the interatomic potential obtained by means of embedded atom method (EAM).

Abstract: It was shown in Ni₅₃Mn₂₅Ga₂₂ single crystals that the annealing at 1273 K for 1 h followed by slow cooling, at which the (L2₁+γ)-structure is formed, provides the increase of crystals plasticity as compared with the brittle initial L2₁-single crystals. The increase of critical stresses by more than 2 times (up to σ > 150 MPa), at which the cooling/heating cycles under stress are accompanied by sample destruction, is observed. Moreover, the value of thermal hysteresis is increased by 1.5 times and the perfect curve of superelasticity is observed at T=423 K.

Abstract: Zinc Oxide (ZnO) is a very promising material. This paper shows the results of the synthesis of hexagonal zinc oxide and its application.

Abstract: The paper describes the axle bearing failure problem and the technological solution involving babbit coating on bronze axle bearing. The structure and properties of anti-friction layer B-16 are described, as well as the technological casting process of bimetal shell.