AMg6 Aluminum Alloy Research Articles

Influence of full-scale climatic tests on the properties of aluminum alloys in zones of river and marine water mixture

Within nine months, comprehensive studies were conducted on the effect of full-scale climatic tests on the properties of samples of aluminum alloy AMg6 when fully submerged in the estuary region of the Don River (the basin of the Sea of Azov) at two stations. The features of the formation of micro- and macro-fouling communities on experimental plates at one, three, six and nine months after the start of the experiment are shown. It is shown that microfouling communities on the experimental plates begin to form within a month of exposure. Diatoms were the background-forming species during the entire practical period of the study. Single macrozoobenthos organisms begin to appear on the samples after three months and only at second station. After six months, macro-fouling organisms are fixed on plates at both stations. As the exposure period increases, the number and biomass of macro-foulers increases. The corrosion resistance assessment of the samples revealed the absence of intercrystalline corrosion during the entire test period in water, at both stations, as well as pitting corrosion during the first six months of exposure.

Critical Dynamics of Defects and Mechanisms of Damage-Failure Transitions in Fatigue.

An experimental methodology was developed for estimating a very high cycle fatigue (VHCF) life of the aluminum alloy AMG-6 subjected to preliminary deformation. The analysis of fatigue damage staging is based on the measurement of elastic modulus decrement according to “in situ” data of nonlinear dynamics of free-end specimen vibrations at the VHCF test. The correlation of fatigue damage staging and fracture surface morphology was studied to establish the scaling properties and kinetic equations for damage localization, “fish-eye” nucleation, and transition to the Paris crack kinetics. These equations, based on empirical parameters related to the structure of the material, allows us to estimate the number of cycles for the nucleation and advance of fatigue crack.

Electrodynamic Treatment of Structural Elements Made of Aluminium and Magnesium Alloys

The article discusses the electrodynamic treatment (EDT) of thin-walled welded structures and EDT equipment, presents results of mathematical modelling concerning the effect of EDT on stresses in welded sheets made of aluminium alloy AMg6 as well as discusses the effect of EDT on the plastic strain mechanism. In addition, the article presents tests results concerning the effect of EDT during the welding of ship structures made of AMg6 plates and discusses the role of EDT in bulge formation. In addition, the article discusses the application of EDT during the repair welding of aero-engine nacelles made of magnesium alloy ML10 and the effect of EDT on openings in an airplane wing stinger in relation to its service life.

Influence of the Accompanying Heating on the Efficiency of Electrodynamic Treatment of AMg6 Aluminum Alloy Welded Joints

Influence of the Accompanying Heating on the Efficiency of Electrodynamic Treatment of AMg6 Aluminum Alloy Welded Joints

To the question of the application of vibrational treatment for brand and whiplash welded compounds from aluminum alloy AMG6 during welding and after its completion

To the question of the application of vibrational treatment for brand and whiplash welded compounds from aluminum alloy AMG6 during welding and after its completion

Математическое моделирование распределения энергии при вводе в материал изделия луча в процессе электронно-лучевой сварки

Modeling of electron beam welding processes is one of the most important parts of applied research, because full-scale experimental investigations are either expensive or highly labor intensive. The problem of modeling the temperature fields at the electron beam entering stage during welding is considered. The aim of the study is to simplify the adjustment of the electron beam welding process technological parameters and to elaborate and develop more efficient control algorithms through replacing full-scale experiments by model ones. The mathematical body of the proposed solutions is constructed using the theories of thermal and welding processes, based on which the energy distribution mathematical models are developed. For practically implementing the computations, an algorithmic support is presented that allows the mathematical models to be applied in modern modeling systems, such as Matlab, Comsol Multiphysics, and Ansys. Apart from supplementing the set of existing mathematical models of the electron beam welding process, the obtained models for calculating the temperature in the beam entering area widen their application for calculating and optimizing the welding process, taking into account the workpiece temperature in the electron beam entering area. By using the proposed solutions, several numerical experiments were carried out for a workpiece made of VT-14 titanium alloy and two pieces of different thickness made of AMg-6 aluminum alloy. The obtained temperature fields and the rms values of process parameters are almost identical with the results of previously conducted full-scale studies.

Chamber Inhibitors of Corrosion of AMg6 Aluminum Alloy

Using a set of physicochemical (ellipsometry and contact angle measurements), electrochemical (potentiometric anode polarization and electrochemical impedance spectroscopy), and corrosion (periodic moisture condensation test) methods, the properties of adsorption films formed on the AMg6 aluminum alloy surface by the chamber method in vapors of some amines of heterocyclic compounds, carboxylic acids, and their salts are studied. It is established that the use of the studied compounds in the chamber processing of the alloy increases—though not effectively enough—its corrosion resistance in a humid atmosphere. The most promising inhibitors are carboxylic acids themselves; the optimum temperature for surface treatment with them is 140°C. One-hour treatment of steel with pairs of oleic, neodecanoic acid, and carboxylic acid A at this temperature gives rise to the formation of nanoscale adsorption films on the AMg6 alloy, which slightly hydrophilize the surface, but possess a protective aftereffect. Apparently, further improvement of chamber protection methods of the AMg6 alloy should consist in the selection of synergists for chamber corrosion inhibitors of the carboxylate type.

Constructive and technological modernization of the aircraft beam

The directions of modernization of welded structures, previously created and serially produced in the aerospace, transport and other industries, are considered. For this, it is proposed to use thermally hardened aluminum alloys as the base metal, and to obtain permanent joints, instead of argon-arc welding, use friction stir welding (FSW), which is performed in the solid phase and has many advantages. Purpose of the work: to show the usefulness of constructive and technological modernization of previously designed and manufactured structures, taking into account the latest achievements in welding, in particular, when creating structures from aluminum alloys using FSW. An example of the modernization of an aircraft beam made of AMg6 aluminum alloy with the help of a FSW is given, which clearly demonstrates how the shape and geometry of the structure are interrelated with the technology of its manufacture.The presented structural and technological options for the modernization of the beam ensured: a decrease in welding stresses and deformations, an increase in the cyclic strength of a structure, savings in materials, labor, time and a decrease in the cost of manufactured products.

Anisotropy Effect of the Mechanical Metal Properties on the Assessment of the Load-Carrying Ability of the Launch Vehicle Oxidant Tank

The paper presents the results of the calculated estimate of the critical pressure level in the oxidant tank of the launch vehicle using generalized diagrams of elastic-plastic deformation of the aluminum alloy AMg6. These diagrams consider the anisotropy of the physical and mechanical properties of the material. The calculation of the stress-strain state is performed using the simplified calculation scheme for the specified structural element of the tank depending on the internal pressure in the axisymmetric statement considering the elastic-plastic deformations. The calculation analysis is based on the mixed scheme of the finite element method, which provides the continuous approximation of displacements and stresses. It allows one to determine the stress-strain state of the tank element with high accuracy. It is implied that the maximum values of stresses and strains occur in the area of the fillet region connecting the ring with the cylindrical shell of the tank. Complying with the obtained data, the calculation of the stress-strain state of the tank element using generalized deformation diagrams, taking into account the anisotropy of physical and mechanical properties and the nature of the load of aluminum alloy AMg6, leads to a more conservative estimate of the critical pressure level as compared with the standard calculation based on the uniaxial tensile diagram.

Algorithm for calculating the distribution of temperature fields at the stage of input and output of an electron beam in the welding process

The article deals with the problem of modeling the distribution of temperature fields at the stage of input and output of an electron beam during welding. The use of such models will make it possible to simplify the adjustment of the technological parameters of the electron beam welding process, as well as the creation and development of more efficient control algorithms by replacing full-scale experiments with model ones. The mathematical apparatus of the solutions proposed in the article is based on the theory of thermal processes and the theory of welding processes, on the basis of which mathematical models of energy distribution are built. For the practical implementation of computations, the article proposes a block diagram of algorithmic support that allows as to apply mathematical models in modern modeling systems such as MATLAB. Using the proposed solutions, a number of numerical experiments were carried out for a product made of VT-14 titanium alloy and two products of different thickness made of AMg6 aluminum alloy. The obtained distribution of temperature fields, as well as the effective values of technological parameters, practically coincides with the results of earlier full-scale studies.

Effect of the Production Conditions on the Structure and Strength of the AMg6 Alloy–12Kh18N10T Steel Bimetallic Joint

The structure and the strength properties of the AMg6 aluminum alloy–12Kh18N10T steel bimetal formed by hot isostatic pressing under various conditions of preparing the contact surfaces of the materials to be joined and various connection media have been investigated. The maximum tensile strength (196 MPa) is reached upon scraping the aluminum components and the presence of a steel surface relief. The maximum bending strength (329 MPa) is reached upon scraping the aluminum components and the absence of steel surface relief.

Effect of Pulse Current on Residual Stresses in AMg6 Aluminum Alloy in Electrodynamic Treatment

The development of energy-efficient methods of controlling the stress state of metallic materials and welded joints is topical for modern production. One of such methods is electrodynamic treatment (EDT). It is based on the passage of electric current pulses (ECP) through the metal, time-synchronized with an impact load initiated by electrodynamic forces. In this case, an electrodynamic deformation process and a process of formation of elastic strain waves occur simultaneously in the material being treated; they are defined as “electrodynamic impact”, the result of which is a local stress relaxation in the metal. The developed mathematical model of the formation of stress and strain fields during EDT, which is based on the motion of an elastoplastic medium, does not take into account the effect of ECPs on dynamic relaxation processes. A computational and experimental assessment of the effect of ECPs, which is based on the experimental assessment of the stress state and microindentation of AMg6 aluminum alloy plates after EDT without and with the passage of ECPs through the metal being treated, has been performed by the mathematical modeling of the EDT process taking into account microindentation results. The passage of ECPs contributes to an increase in tensile plastic strains and hence to an increase in residual compressive stresses (provided that the specimens to be treated are rigidly fixed). The reliability of the procedure has been confirmed by the results of evaluating the distribution of residual welding stresses in AMg6 alloy butt joints after EDT.

Publisher’s note

This article refers to:Hot cracking susceptibility of commercial filler metals for Alloy 617 by Varestraint test. Study of hot cracking of Alloy 617 in multipass weldsTomographic measurement of current density and heat input density for tilting TIG arcIn-situ measurement of weld quality during MAG welding using laser ultrasonicPrevention of cold cracking by the welding process for reducing diffusible hydrogen in high-tensile thick plate weldingFundamental plasma diagnostic study for guiding TIG arc phenomenon by laser beam irradiationEffect of weld line shape on laser welded joint strength of automotive high-strength steel sheetsCharacteristics of material flow in friction stir spot welding tools in consideration of cutting toolsInvestigation of relationship between resistance spot welding condition and nugget shape by utilizing machine learning based techniqueHot cracking susceptibility and solidification segregation analysis by computer simulation in duplex stainless steelsStudy on welding phenomena observation method based on arc and molten pool light emission characteristics in visible and infrared wavelength region – development of image sensing technology for in-process welding monitoring technologyInfluence of thickness reduction in base plate on elastic stress state of patch plate joint by combination of welding and bondingProposal and applicability of a method to evaluate surface tension of liquid using large volume sessile drop in gravityInfluence on factors of cold crack formation factors of a steel 10G2FBYu welded joint by regulating linear energyTechnological features of the porous functional ceramic coatings formation on aluminium by the method of microarc oxidation in silicate electrolytesImproving friction stir welding toolFeatures of pulsed laser welding with deep fusion penetrationFormation of undetachable mechanical joints by cold plastic deformationFixed joints of dispersion-hardened composite materials based on aluminium, made by friction stir weldingHigh-temperature brazing of structural elements for the first wall of the DEMO reactor with rapidly hardened tungsten and steel alloys-soldersThe influence of the welding circuit magnetic field on the formation of the joint at unsupported weldingFeatures of the heat generation process at ultrasonic welding of polycarbonate under independent pressureInduction brazing of carbide cutters for a mining tool. The choice of composition and solder formEvaluation of residual stresses and structural-phase composition in longitudinal welds of high pressure pipesFinite element modelling of the stress-strain state in specimens from dissimilar Ni-based alloys during pressure welding with displacementFor creating layered composite materials based on monocrystalline silicone for gradient heat measurement based by diffusion welding methodStudy of joints for heat-resistant alloy XN55MVTs obtained by diffusion weldingMechanical properties of aluminium alloy AMg6 obtained by wire electron beam additive formingCalculation of the transverse magnetic field parameters, allows the mixing of the melt in the bath during electric arc deposition and welding

A study of the electrolyte composition influence on the structure and properties of MAO coatings formed on AMg6 alloy

The influence of electrolysis conditions at different electrolyte compositions on the phase formation and properties of coatings obtained by microarc oxidation (MAO) on an aluminum alloy AMg6 was studied. For electrolysis, three types of electrolytes were used: alkaline electrolyte ((KOH) solution in distilled water), silicate electrolyte (with different percentages of Na 2 SiO 3 component) and complex alkaline silicate electrolyte with liquid glass (1÷12 g/l Na 2 SiO 3 ) and potassium hydroxide (1÷6 g/l KOH). An analysis of the results showed that the choice of electrolyte type and conditions of the microarc oxidation process allows a wide variation in the phase-structural state, thickness and properties of the AMg6 aluminum alloy. The criterion for the expected phase-structural state of the coatings as a result of microarc oxidation is the completeness of the γ–Al 2 O 3 →α–Al 2 O 3 transformation process during coating formation. The use of an alkaline electrolyte does not allow achieving a high hardness of the coating due to the formation of the γ-Al 2 O 3 phase and the absence of thermodynamic conditions for the γ–Al 2 O 3 →α–Al 2 O 3 transition. When using a silicate electrolyte, it is possible to significantly increase the growth rate of the coating, but at the same time, the presence of a large specific Si concentration stimulates the formation of mullite and an amorphous-like phase. The use of a combined alkaline silicate electrolyte (with different percentages of KOH+Na 2 SiO 3 ) with a low content (6 g/l) of Na 2 SiO 3 in solution stimulates the formation of mullite. This is manifested to the greatest extent with the lowest content (1 g/l) of the KOH component. At a higher content (2 g/l) of the KOH component, the processes characteristic of an alkaline electrolyte become dominant. This leads to an incomplete transformation reaction and the formation of only the γ-Al 2 O 3 phase. The achievement of the thermodynamic conditions of the γ–Al 2 O 3 →α–Al 2 O 3 conversion became possible with an increase in the specific Na 2 SiO 3 content in the electrolyte solution to 12 g/l. In this case, MAO coatings were formed on the AMg6 alloy with the highest hardness of 1500 kg/mm 2 and high electric strength of 12 V/μm

Increase in the life of welded joints of AMg6 aluminum alloy

Increase in the life of welded joints of AMg6 aluminum alloy

Підвищення довговічності зварних з’єднань алюмінієвого сплаву АМг6

Підвищення довговічності зварних з’єднань алюмінієвого сплаву АМг6

RESEARCH OF DEVELOPMENT CONDITIONS OF STRUCTURAL TRANSFORMATIONS DURING FRICTION STIR WELDING OF MULTIPHASE ALUMINUM ALLOY

Purpose. We aim to investigate the development conditions of structural transformations during friction stir welding (FSW); establish the nature of individual influence of structural components in achieving superplastic flow conditions; determine the influence nature of grain size on the groundmass microhardness during FSW. Methodology. Friction stir welding was performed on specially designed equipment. The material was 2.9 mm thick AMg6 aluminum alloy plates with the chemical content of alloying elements within the grade composition. The temperature and pressure from the tool on the edges during welding were determined on a specially designed stand. The tool pressing force to the metal was measured with a dynamometer type DC-0.1. Microhardness measured on the PMT-3 device with the indentation load of 0.05 N was taken as a characteristic of alloy microvolumes strength. Findings. Different degrees of rotation of the working tool and normal pressure to the edges determined the degree of metal heating and the quality of the seam formation. The influence degree of the technological parameters of the FSW on the metal heating temperature in the area of the working tool shoulder is estimated. The development of recrystallization processes in the conditions of two-phase alloys is considered. It has been shown that collective recrystallization is less determined by the volume fraction of the second phase, its dispersity and ability to interact with the metal matrix. The effect of the temperature gradient on the microhardness for the structures of the heat-affected zone is estimated under conditions of a practically unchanged grain morphology. Originality. The conditions for the development of structural transformations during friction stir welding and the influence mechanism of grain size on the matrix microhardness are determined. Exceeding the optimum temperature in the joint area during welding contributes to the diffusion accelerating along the boundaries between phases and grains, resulting in the formation of a concentration gradient of alloying elements and, first of all Mg, increasing the hardening effect of the solid solution state. Practical value. According to the results, the additive character of the hardening from the influence of the solid solution and grain boundaries under the conditions of superplastic flow is determined. A state close to the superplastic flow is achieved by reducing the effect of hardening the solid solution and increasing the contribution from the small grains boundaries. Achieving a state of superplastic deformation is possible by minimizing the effect of strain hardening.

Features of the use of light alloys in the marine climate of the arctic zone

The movement of mining and processing industries to the North poses the task of analyzing the performance of materials traditionally used in structures and products. The paper presents the results of comparative studies of magnesium alloy MA2-1 and aluminum alloy AMg6 in the marine climate of Northern latitudes. The studies were carried out after simulating the long-term operation and storage of alloys in northern latitudes, namely after long 1000-hour exposures at a temperature of -600 ° C, aging in a salt fog chamber. We analysed the impact of external climatic factors, typical of northern latitudes, on the mechanical properties and a comparative assessment of the corrosion resistance of alloys in a marine climate.

Features of the structure and properties formation of AMG6 alloy under the equal channel angular pressing

The results of experimental studies of changes in the structure, microhardness, and wear resistance of the AMG6 aluminum alloy during equal channel angular pressing (ECAP) are presented in this work. The evolution of the fine structure and the formation of secondary phases in the AMG6 alloy during ECAP were studied. The dark-field image of the structure of the AMg6 alloy in the matrix reflex showed the splitting of the material into small disoriented fragments of about 0.5 μm in size with a small-angle disorientation boundary (about 2–5°). Optimal method and modes of ECAP of the AMG6 aluminum alloy were selected of the bases of experimental research, which make it possible to obtain a workpiece with enhanced tribological and mechanical characteristics. It was established that the most intensive grinding of the grain structure in the AMG6 alloy occurs at ECAP-12 at a channel angle intersection of 120°. It is shown that with a decrease in grain size, the microhardness of the alloy AMG6 after ECAP increases by 4 times, compared with the initial state.The results of the test samples for abrasive wear showed a decrease in mass loss after 12 passes of ECAP, which indicates an increase in the wear resistance of the alloy AMG6 by 13–14 %, compared with the initial state.

Влияние условий получения на структуру и прочность биметаллического соединения сплав АМг6—сталь 12Х18Н10Т

Влияние условий получения на структуру и прочность биметаллического соединения сплав АМг6—сталь 12Х18Н10Т