106 Works

Experimental study and modeling of changing mechanical properties in tempering of bainitic-martensitic steels

A.A. Vasilyev , D.F. Sokolov & S.F. Sokolov
Dependences of mechanical properties (yield stress, tensile stress, relative elongation) and impact toughness on the tempering time at various temperatures have been investigated for 10 industrial bainitic-martensitic steels with a wide range of chemical compositions (C(0.04-0.27), Mn(0.33-1.57), Si(0.22-1.09), Cr(0.02-1.14), Ni(0.01-3.74), Cu(0.02-1.03), Mo(0.01-0.43), Nb(0.002-0.044), V(0.003-0.200), Ti(0.001-0.045), B(≤0.003) (mass.%)). Based on the obtained experimental results, a quantitative model is developed to predict the mechanical properties of the considered steels after tempering. The modeling results comply well with...

NUCLEAR GEOMETRY: SODIUM, MAGNESIUM, ALUMINUM

Alexander I. Melker
The nuclear geometry has been developed by analogy with the fullerene geometry. On the basis of this geometric approach, it was possible to design the structure of sodium, magnesium and aluminum isomers and their isotopes, which can be obtained by means of nuclear synthesis. The most stable nuclei can be classed into two groups: basic nuclei having equal number of protons and neutrons and isotopes having one or two more neutrons. The latter ensure their...

ANALYTICAL DESCRIPTION OF QUANTUM EFFECTS AT CURRENT FILAMENTATION IN CHALCOGENIDE GLASSES

N. Sovtus & K. Mynbaev
Quantum effects occurring during current filamentation in a chalcogenide glass are considered. Under the conditions considered, the current filament appears as a set of concentric tubes with different temperatures. In every tube, the electron has a specific wave function and a specific energy level. The radii of the tubes appear to be proportional to natural numbers n. The dependence of maximal temperature on the electrical field is obtained. The Schroedinger equation is reduced to the...

INVESTIGATION OF MULTISCALE MECHANISMS OF DYNAMIC DEFORMATION AND FRACTURE OF 1565 ALUMINUM ALLOY UNDER PLANE COLLISION AND HIGH-VELOCITY PENETRATION

Yu.I. Meshcheryakov, G.V. Konovalov Konovalov, A.K. Divakov, N.I. Zhigacheva & Е.P. Osokin
High strength 1565 aluminum alloy was tested within impact velocity range of 250- 750 m/s in two schemes of shock loading: (i) under uniaxial strain conditions and (ii) in highvelocity penetration. The combination of load regimes allows the different stages of multiscale structure formation to be retraced. The intensity of macro-meso momentum exchange is found to be responsible for both resistance to spallation and high-velocity penetration. The overall impact velocity region is found to be...

THE INFLUENCE OF TURMERIC MICROPARTICLES AMOUNT ON THE MECHANICAL AND BIODEGRADATION PROPERTIES OF CORNSTARCH-BASED BIOPLASTIC MATERIAL: FROM BIOPLASTIC LITERATURE REVIEW TO EXPERIMENTS

F. Triawan, A.B.D. Nandiyanto, I.O. Suryani, M. Fiandini & B.A. Budiman
The purpose of this study was to investigate the effects of turmeric microparticles amount on the mechanical and biodegradation properties of cornstarch-based bioplastic material. To produce the bioplastics, several steps were done sequentially: (1) dissolving a mixture of cornstarch, glycerol, and acetic acid in aqueous solution; (2) adding turmeric microparticles with a specific amount (i.e., 0.50; 0.75; 1.00; 1.50% (w/w)); (3) homogenizing the mixture at temperature of 60ºC; (4) molding process; and (5) drying process...

MECHANICAL PROPERTIES OF AlSiMg/SiC AND AlSiMgTiB/SiC PRODUCED BY SEMI-SOLID STIR CASTING AND HIGH PRESSURE DIE CASTING

S. Sulardjaka, Sri Nugroho & Norman Iskandar
Mechanical properties of the AlSiMg/SiC and AlSiMgTiB/SiC composites produced by high pressure die casting (HPDC) are investigated. The mixture of ADC 11, master alloy AlMg, master alloy AlTiB and 99 % aluminium were used as metal matrix. A reinforcement particle was represented by high purity silicon carbide with an average particle size mesh 400. Aluminium matrix and SiC particle with the content: 5 %, 7.5 %, and 10 % wt were mixed by the semi-solid...

JUMPING AT STRAIN RECOVERY IN SHAPE MEMORY Cu-Al-Ni SINGLE CRYSTALS

V.I. Nikolaev, R.B. Timashov, S.A. Pulnev, L.I. Guzilova, P.N. Butenko & S.I. Stepanov
Shape memory Cu-Al-Ni single crystals of two alloy compositions Cu 82.5 wt.% - Al 13.5 wt.% - Ni 4.0 wt.% and Cu 81.98 wt.% - Al 14.02 wt.% - Ni 4.0 wt.% have been studied in view of their ability to undergo spontaneous jumping during reverse martensitic transformation. Crystals of both alloys were compressively deformed up to a full shape memory strain (8%) at room temperature. It was found that specimens of the first alloy...

MELT RHEOLOGICAL BEHAVIOUR AND MECHANICAL PROPERTIES OF POLY(LACTIC ACID)/HIGH DENSITY POLYETHYLENE BLENDS

Fadi Alzarzouri, Rafi Jabra & Fawaz Deri
In this study, poly(lactic acid) was melt blended with high density polyethylene to investigate the rheological and mechanical properties of these blends. The rheological properties were characterized where viscous properties were evaluated in the molten state. In studying the viscous properties, non-Newtonian index (n), apparent viscosity, and the flow activation energy were determined. Mechanical properties were studied in terms of tensile properties, i.e. ultimate tensile strength, Young's modulus, elongation, and total energy at fracture. The...

INFLUENCE OF THE SIZE OF TURMERIC MICROPARTICLES REINFORCING AGENT ON MECHANICAL AND BIODEGRADATION PROPERTIES OF CORNSTARCH-BASED BIOPLASTIC MATERIAL: CURRENT STUDIES, EXPERIMENTAL RESULTS, AND PROPOSAL MATERIAL CRACK PHENOMENA DURING MECHANICAL TESTING

A.B.D. Nandiyanto, F. Triawan, M. Fiandini, I.O. Suryani & G.K. Sunnardianto
The purpose of this study was to investigate the effect of sizes of turmeric microparticles (as a reinforcing agent) on the mechanical and biodegradation properties of cornstarch-based bioplastic material. The following fabrication procedures were performed: (1) diluting cornstarch in water; (2) making homogeneous mixture of cornstarch, glycerol and acetic acid by heating at less than 100ºC, (3) additional turmeric with a specific size (i.e. 250, 125, 100, 74 μm); (4) molding process; and (5) drying...

Effect of trace impurities on the thermoelectric properties of commercially pure aluminum

M.S. Kaiser
Impurities play an important role in the properties of aluminum. Those are incorporated into commercially pure aluminum through repeated melting and samples are characterized for their thermal conductivity, dielectric and morphological properties as a function of cold deformation and annealing temperature. Results indicate that cold rolling increases thermal conductivity since reduces the porosity like defects but heavily coldworking decreases the conductivity because of distorts the crystal lattice. Material defects are more prominent than impurities in...

Properties of 13% chromium wire electric arc spraying coatings

V.M. Gusev, O.Y. Elagina, I.V. Volkov & A.V. Buryakin
The article considers the nature and some mechanical properties of corrosionresistant metallizing steel coatings produced out of 13% chromium wires. The carbon is confirmed to influence on the phase composition, hardness, adhesion strength of the coating to the substrate, elasticity module and bending strength of the coating material. The authors estimated a relative wear resistance of sprayed coatings under abrasive friction. They showed the data on the adhesion strength and elasticity module of the coating...

Crystallographic texture of industrial automotive steels and effect of tertiary cementite dissolution on its development

Alexander A. Vasilyev, N.Y. Zolotorevsky, Dmitry F. Sokolov & S.A. Philippov
X-ray investigation of crystallographic texture and its correlation with r m value (Lankford coefficient) was performed on a representative set of industrial automotive steels of different grades. Though the majority of steels had the structure of polygonal ferrite with small fractions of pearlite in the hot rolled condition, steels with a more complex structure were also included in the study. For this set of steels, a linear dependency has been shown to hold between r...

Response of fine-grained fiber-reinforced concretes under dynamic compression

A.M. Bragov, M.E. Gonov, D.A. Lamzin, A.K. Lomunov & I.A. Modin
The article presents the results of tests of different types of fiber-reinforced concrete in comparison with concrete-matrix. The dynamic experiments were carried out using the split Hopkinson bar technique on samples of fine-grained concrete-matrix, as well as with the addition of steel and polypropylene fiber. The static tests of these materials were carried out using the Z100 Zwick-Roell testing machine. Diagrams of deformation and dependences of maximum stresses versus the stress rate are constructed. The...

SPECIFICS OF SYMMETRY CONDITIONS IN GRADIENT ELASTICITY THEORIES

S.A. Lurie, P. Belov & E. Lykosova
The conditions of symmetry of the common Mindlin types gradient theories of elasticity, which characterize the specificity of these theories in comparison with the classical theory of elasticity, are investigated. We discuss the symmetry conditions of the tensors of the moduli of elasticity of the sixth rank under the permutation of the differentiation indices, which are consequence of the fact that the second derivatives of the displacement vector do not depend on the order of...

Effect of grain size distribution on the yield strength of metal-graphene composites

S.V. Bobylev & A.G. Sheinerman
A theoretical model describing effect of grain size distribution in the metal matrix of metal-graphene composite on its yield strength. The model describes the initial stage of plastic deformation in metal-graphene composites and takes into account both dislocation mechanisms of plasticity and the process of grain boundary sliding. The yield strength of aluminum-graphene composite was calculated depending on the average grain size of the matrix and the volume fraction of graphene. Our analysis shows that...

NUCLEATION AND GROWTH OF FULLERENES AND NANOTUBES HAVING FOUR-FOLD SYMMETRY

Alexander I. Melker, Maria A. Krupina & Aleksandra N. Matvienko
We have studied possible ways of generating and growing the fullerenes having four-fold symmetry. Beginning with cyclobutane C4H8 and clusters C8, we obtained elementary fullerenes C8 and mini-fullerenes C16, which produce the following fullerenes from C24 to C64, perfect (basic) and imperfect, as well as nanotubes. The imperfection is connected either with extra 'interstitial' or 'vacancy' carbon dimers, both types of dimers playing the role of defects. Only the basic fullerenes C24, C32, C40, C48,...

ON THE ISSUE OF ANALYTICAL DERIVATION OF STRESS STATE IN A CYLINDRICAL SHELL WITH A CIRCULAR HOLE UNDER AXIAL TENSION

S.V. Kashtanova, A.V. Rzhonsnitskiy & A.A. Gruzdkov
The stress field in the cylindrical shell with the circular hole is considered. Thoroughly analyzing previous works we concluded that up to the present there are no explicit formulae useful for applications despite numerous works on this subject. Moreover, the classical analytical approach lacks a rigorous mathematical foundation. Its applicability is limited to cases that slightly differ from the plane Kirsch problem. The numerical results of various researches show a significant discrepancy. This paper proposes...

Deformation mechanism of bimodal metal-graphene composites with nanotwinned structure

N.V. Skiba
The theoretical model is suggested which describes micromechanisms of plastic deformation in bimodal metal-graphene composite consisting of large grains embedded into nanocrystalline/ultrafine-grained metal-matrix reinforced by graphene inclusions. In the framework of the model, lattice dislocation slip and grain boundary sliding has occurred in nanocrystalline/ultrafine-grained matrix, and lattice dislocation slip and migration of twin boundaries are realized in large grains with a nanotwinned structure providing the plastic deformation of bimodal metal-graphene composite. With this assumption, the...

Axial compression behavior of thin-walled mild steel tubes subjected to axial impact

S.K. Tak & M.A. Iqbal
The finite element computations were performed on ABAQUS/Explicit solver to study the effect of wall thickness on axial crushing and energy absorption of the mild steel tubes under axial impact. Circular tube (60 mm diameter) and square tube (47.34 mm size) with varying wall thicknesses (1.1, 1.5, 2, 2.5, and 3 mm) were impacted axially by 5 kg projectile. A comparative study has also been carried out on axial compression behavior of tubes with circular...

Post-dynamic recrystallization in a heavily alloyed Ni-based superalloy

A. Ganeev, R. Zainullin, R. Shakhov, S. Mukhtarov & V. Imayev
The work is devoted to a study of post-dynamic recrystallization in a recently developed nickel-based superalloy SDZhS-15 manufactured by ingot metallurgy and intended for disc applications. The as-cast superalloy was subjected to long-term homogenization annealing and canned forging at subsolvus temperatures (T=Ts-(40-70), where Ts is the γ′ solvus temperature) under quasi-isothermal conditions. This led to the formation of a refined recrystallized fine-grained structure with individual non-recrystallized γ grains in the central part of the forged...

The evolution of brake friction materials: a review

Naveen Kumar, Ajaya Bharti, H.S. Goyal & Kunvar Kant Patel
Today, in the fast-moving world, the focus of all automobile companies is to increase the speed of vehicles to reduce travel time. With an increase in the speed of vehicles, there is an urgent need for the development of friction materials suitable for high-speed braking applications. A historical review of various materials used to date for making brake pads and brake drum/disc is done in the present work. Asbestos was the most suitable and widely...

Effect of temperature on Charpy impact response of laminated glass structures

Dural Ebru
For the structural purpose, the usage of laminated glass units in the modern construction industry is becoming widespread. Laminated glass units are manufactured using glass layers bonded together with interlayer materials. When the laminated unit is shattered, the interlayer prevents large and sharp pieces. This property makes laminated glass a safety glass, which prevents injury and even death of people. The current study is about the effect of temperature on the impact behavior of laminated...

An investigation on the growth of fatigue crack between sequentially cold expanded adjacent circular holes in Al 7075 - T651 alloy

S. Anil Kumar &  N.C. Mahendra Babu
Critical structural holes located in close proximities are sequentially cold expanded one after the other in series to enhance their fatigue strengths by inducing beneficial residual stresses around hole regions. In some instances, where, several holes are closely located, the cold expansion–induced beneficial residual stress fields in the regions between the holes are considerably different in comparison to the case of cold expansion of a single hole that is free from a proximity hole. Therefore,...

Modeling of carbides and copper particles precipitation during tempering of bainitic-martensitic Cr-Mo-V-Cu steels

A.A. Vasilyev, S.F. Sokolov & D.F. Sokolov
The paper represents a model for the tempering effects on quenched bainitic-martensitic steels that describes both the recovery and precipitation phenomena. The latter involves various carbides (Fe3C, V4C3, Mo2C, Cr7C3) and particles of pure Cu. Thermodynamic driving forces in the nucleation of the considered particles have been calculated using empirical formulas obtained with the Thermo-Calc software. The predicted formation kinetics for the considered carbides and Cu particles complies well with relevant experimental data.

The mechanical properties improvement of thermoplastics-based fiber metal laminates

Dmitry Goncharenko, Ilya Kobykhno, Elizaveta Bobrynina & Oleg Tolochko
This study investigated the possibility of increasing the fiber metal laminates mechanical properties by improving the impregnation quality due to the addition of a different number of layers of polymer film on the prepreg-metal interface. Specimens were made based on two thermoplastic polymers (polyamide-6 and polypropylene), glass fibers (E-glass), and aluminum alloy (AlMg6) by hot pressing. The theoretical calculation was performed for the tensile strength according to the rule of mixtures. The dependences of tensile...

Registration Year

  • 2021
    106

Resource Types

  • Text
    106

Affiliations

  • Peter the Great St. Petersburg Polytechnic University
    18
  • Institute of Problems of Mechanical Engineering
    12
  • Ioffe Institute
    6
  • St Petersburg University
    5
  • Motilal Nehru National Institute of Technology
    5
  • Indian Institute of Technology Roorkee
    3
  • Russian Academy of Sciences
    3
  • Institute of Metal Superplasticity Problems
    2
  • Kurukshetra University
    2
  • N. I. Lobachevsky State University of Nizhny Novgorod
    2