AMg6 Aluminum Alloy Research Articles

Adjustment of a rotated mirror analog of the Abbe prism

A construction of a mirror system manufactured from the AMg-6 aluminum alloy by diamond microsharpening and intended to take the place of the rotary Abbe prism in the infrared spectrum region is presented. Using the technique of reducing a three-mirror system to the simplest mirror equivalent and vector-matrix method, primary errors of a mirror system are revealed and their influence on the picture bounce is studied. An adjustment technique adapted to a real construction is developed for a mirror system.

Application of Photometric Data to Estimation of the Deterioration of Fatigue Properties of an AMg6 Alloy*

The method of constructing the fatigue curves by photometric data obtained in surface analysis of three-four flat specimens, fatigue-tested in cantilever bending, was examined using an AMg6 aluminum alloy as an example. Before and after experiments the test portions of each specimen are scanned, and the durability of their fragments is assessed at known stress amplitudes by the generated data.

Study of mechanism and kinetics of wear of shearing dies from semi-heat-resistant steels in machining articles made from various structural materials

based on the experimental research findings, the systematization of wear mechanisms of working elements of shearing dies when machining various materials characteristic of sheet-metal stamping (low-carbon steel 08Yu, aluminum alloy AMG-6, corrosion-resistant steel 12Kh18N9T, and carbon steel U8) is presented. Four standard wear-resistant coatings are proposed to achieve an increase in the efficiency of the working elements of shearing dies at various operating loads and wear mechanisms.

Computer simulation of the production process for isothermal forging of profiled panels made of aluminum alloys

The possibility of simulating the operating procedure for the isothermal forging of a profiled forged piece of an AMg6 aluminum alloy is investigated with DEFORM-3D software. The simulation uses the following boundary conditions. The deformation rate is 10−4-10−3 s−1, deformation resistance is 60 MPa, and the friction factor is 0.1. It is shown that the computational model correctly describes the actual production process for the die isothermal forging, which allows us to recommend this software for designing the production process for obtaining profiled forged pieces made of aluminum alloys.

Study of fluoride ions adsorption by thermally treated products of electrochemical dimensional treatment of the AMG-6 aluminium alloy

Adsorption of fluoride ions from aqueous solutions (fluoride ion concentration of 10−4−3 × 10−1 M) by products of electrochemical dimensional treatment of the AMG-6 aluminum alloy subjected to thermal processing at 100, 200, 400, and 600°C was considered. Conditions defining adsorption equilibrium of fluoride-ions in a bulk solution and on its surface were analyzed.

Effect of solution temperature and ph on adsorption and density of surface charge at aluminum oxyhydroxide /NaF aqueous solution interface

The effect of temperature, pH, and adsorbed fluorine on the density of a surface charge at the aluminum oxyhydroxide /NaF aqueous solution interface is investigated using the method of potentiometric titration. The equilibrium of fluorine ion adsorption in analyzed. Products of electrochemical dimensional machining (ECDM) of an AMG-6 aluminum alloy thermally treated at 200°C are used as an adsorbent. The experiments on the adsorption have been carried out from an acetated buffer with the initial fluorine solution concentrations from 1.0 × 10−3 to 1.5 × 10−1 M/l. The adsorption isotherms were plotted for solution temperatures of 20, 30, and 40°C. Adsorption is shown to obey the Langmuir adsorption model. It is demonstrated that, at all solution temperatures, the pH is 5 for the maximal fluorine adsorption on aluminum oxyhydroxide. It has been revealed that the surface charge at the aluminum oxyhydroxide /NaF aqueous solution interface depends on the solution temperature; i.e., the pH of a point of a zero charge point (pHPZC) of the aluminum oxyhydroxide surface decreases with an increase in temperature. As is the case with temperature, adsorbed fluorine shifts pHPZC toward smaller values, which is typical for specific adsorption. The temperature dependence of pHPZC has made it possible to determine the standard mole enthalpy and entropy of surface-charge formation. The interaction of fluorine with aluminum oxyhydroxide is shown to be the result of the chemical affinity of F with surface centers of AlOH2+ and AlOH and electrostatic attraction.

Effect of inhibiting additives on the electrochemical behavior of AMg-6 alloy in aqueous potassium acetate solutions at elevated temperatures

The electrochemical behavior of AMg-6 aluminum alloy in an aqueous acetate solutions with additions of sodium hydrophosphate, sodium benzoate, and benzotriazol at enhanced (up to 70°C) temperatures is studied. It is found that the time-resistant protective layers are formed upon the introduction of small amounts of sodium hydrophosphate (≤1%) or a mixture of sodium hydrophosphate and benzotriazol (0.5% Na2HPO4 + 0.2% BTA).

Radiation annealing of AMg6, 1441, and VD1 aluminum alloy strips using a ribbon source of accelerated ions

The results of our earlier studies are summed and new data are presented on the influence of beams of accelerated Ar+ ions on the mechanical properties and structure of various commercial aluminum alloys. A short-time (5–60 s) ion-beam processing of cold-deformed alloys is shown to lead to their softening, which is analogous to that upon intermediate annealing at 320–400°C for 2–3 h used in cold rolling. An experimental ribbon ion source, which is intended for in situ processing of rolled sheets in a rolling line to remove strain hardening instead of long-term furnace annealing, is described.

Effect of submicrocrystalline structure and inclusions on the deformation and failure of aluminum alloys and titanium

The effect of the original structure on deformation and failure in tension for submicrocrystalline aluminum alloys AMg6, Al-6.2% Mg-0.24% Sc and titanium is studied after rapid plastic deformation by equal channel angular extrusion. Combined analysis of deformation curves and acoustic emission, and also the results of metallographic and fractographic studies are provided. The effect of submicrocrystalline structure and inclusions on plastic flow resistance and failure in tension for alloys is studied.

Correspondence principles for complex shear characteristics in a nonisothermal model of monoharmonic approximation for physically nonlinear materials

The Bodner–Partom nonisothermal flow model and the generalized method of harmonic linearization are used to calculate the complex shear modulus and compliance for AMg-6 aluminum alloy. The strainand stress-controlled cycles of loading in the temperature range 20–400°C are considered. The correspondence between the shear modulus and the compliance is studied. It is similar to the inverse proportionality condition in the theory of linear viscoelasticity. It is established that representing the modulus and compliance as functions of the strain amplitude is better than as functions of the stress amplitude due to the universal description of the characteristics for soft and hard cycles and high accuracy of correspondence

Temperature influence on the equilibrium and kinetics of fluoride-ion adsorption by heat-treated Al oxyhydrates

The effect of temperature on the fluoride adsorption by heat-treated samples of aluminum alloy AMG-6 electrochemical machining products has been studied. Kinetic curves and adsorption isotherms at solution temperatures of 20, 30, and 40°C have been received, and the adsorption rate constants, diffusion coefficients, and the values of the activation energy have been determined. The obtained Ea value corresponds to values of the activation energy characteristic of ion exchange processes controlled by internal diffusion. Thermodynamic functions of the adsorption process ΔF0, ΔH0, and ΔS0 have been calculated. The differential free molar energy changes, the isosteric heat, and the entropy of the fluorine adsorption have been analyzed versus the filling degree of the sample surface with fluorine ions. The absence of the process rate dependence on the mixing rates, as well as the character of the dependences of F (equilibrium degree reaching, %) on the √tdemonstrates that the process under consideration is controlled by an internal diffusion step. The mechanism of fluorine ion fixation on the modified surface of aluminum oxyhydrates has been discussed.

AN EXPERIMENTAL STUDY OF BUCKLING OF CYLINDRICAL SHELLS SUBJECTED TO STATIC AND DYNAMIC AXIAL IMPACT

To study structure resistance to impact loads using thin-wall cylinder units, knowledge of energy absorption parameters of these test units is required, as well as evaluations of resistance force. Buckling of cylinder test units involves formation of both axisymmetric and non-axisymmetric folds. Repeatability of buckling patterns is an important parameter of the fold formation process and, eventually, of the absorbed energy magnitude. This paper discusses buckling patterns obtained for cylinder test units of three dimension types with scales relating as 1:2:10. The units were made of three materials (steel 09G2C and two aluminum alloys, AMg6 and AMcM) and subjected to static and impact loading. For static loading, a test unit was fixed on a long measuring rod and subjected to an impact by a projectile moving at a speed of V0. The experiments were performed at three loading speeds V0 10m/s, 50 m/s, 100 m/s. No less than 5-10 tests were performed for each type of test units, i.e. for each size, material and load level, to study buckling repeatability. Impact velocity and axial compression force history were recorded in the tests. It was obtained in the testing of cylinder test units that: Repeatability of buckling patterns was observed only in the formation of the first fold, which is axisymmetric. Then buckling, in most cases, follows a non-axisymmetric path; -With test unit scale (i.e. size) increasing, its relative energy absorption capacity under impact loading (in ratio to the test unit mass) increases; - There is clear evidence that strain rate influences the material strength properties, except for the aluminum alloy AMg6, whose strength properties depend rather weakly on strain rate. These experimental findings can be used as a benchmark for verification of computer codes, as well as to study the behaviors of cylinder test units subjected to axial impact, which involve both axisymmetric and non-axisymmetric buckling shapes.

Fluorine adsorption by aluminum oxihydrates subjected to thermal treatment

The adsorptive behavior of fluorine ions by the products of electrochemical machining (AMG-6 aluminum alloy samples) subjected to thermal treatment at temperatures of 100, 200, 400, and 600°C was investigated. The regimes were analyzed, which determine the steady-state distribution of fluorine between the bulk solution and the solid surface. All the samples exhibited good adsorptive properties for fluorine removal; the AMG-200 sample was the most efficient. The kinetic curves and adsorption isotherms were plotted. It was shown that the increase in the solution temperature lead to an increase in the adsorptive capacity for all the samples. This gave evidence of the chemical nature of the investigated process. The following mechanism of fluorine fixation on the modified surface of aluminum oxihydrates was proposed: the anion exchange of F−-ions with surface OH−-groups with formation of covalent bonds, which further transform into ionic bonds.

Compressive and shear resistance of materials under dynamic rates of load application

The dynamics of formation of stresses and strains and of strain rates due to compressive and shear deformation of about 103 sec−1 in impact tests performed with the use of a Hopkinson split bar is considered. At an impact speed of up to 400 m/sec the stresses and the strain rate before failure are shown to oscillate at a high frequency (40–100 Hz). It is shown that the fracture resistance of aluminum alloys AMg6 and V95, of steel KhVG, and of ceramics from silicon carbide and alumina differs substantially under static and dynamic loads; the difference also depends on the kind of stress state.

Experimental and numerical analysis of high strain rate behavior of aluminum alloys AMg-6 and D-16

Results of experimental investigation and numerical modeling of high strain rate behavior of aluminium alloys AMg-6 and D-16 are presented. Using Split Hopkinson Pressure Bar (SHPB) parameters of Johnson-Cook's model and other models from LS-DYNA library were determined in strain rate range 10 2 -10 4 s -1 . For verification of the models a comparison of the results of numerical modeling and model experiments was carried out. Modificated Taylor's test and modification of SHPB test for high-speed penetration were carried out as model experiments.

On the prediction of the fatigue life of thin-walled structures based on a statistical model

We present experimental results of fatigue tests of AMg6 aluminum alloy model specimens-plates with a single notch, subjected to fully reversed and asymmetric cyclic axial loading. The experimentally determined lives of model specimens are used as the results of the base experiment for predicting the fatigue strength characteristics of large-scale cylindrical shells with circumferential ring-shaped stress raisers loaded by axial forces of a cyclic nature. A numerical study has been performed of the statistical model adopted for predicting the fatigue life of such shells.

Jumplike Deformation in AMg6 Aluminum Alloy in Tension

A hypothesis for the relationship between jumplike deformation in AMg6 aluminum alloy under stress-controlled static tension loading and fracture of secondary-phase dispersed inclusions is presented and substantiated. The values of jumplike deformation increments have been found to depend on the size of dispersed phases and their distribution in the alloy. A procedure is put forward for predicting jumplike deformation in the alloy on the basis of histograms of distribution of dispersed particles in the initial material.

Degradation of Aqueous Pentadecane Emulsion by an Anodic Microdischarge: 5. Comparison with Other Alkanes

Hydrocarbon degradation in tridecane, decane, and octane emulsions by the action of anodic microdischarge (carbonate electrolyte, AMg-6 aluminum alloy anode, voltage 600 V, current 50–100 mA) was studied. It was shown that processes occurring in these emulsions (formation of polycondensate and hydrocarbon gases) are the same as in the case of pentadecane emulsion; however, the relative contribution of the observed degradation pathways depends on the hydrocarbon chain length.

Rheological Model of Flow of a Material with a Variable Structure under Superplastic Deformation

Versions of rheological models describing the phenomenological behavior of materials in the superplasticity state with allowance for the elastic component and without allowance for it have been presented. Consideration has been given to the basic indications of manifestation of superplastic properties from the viewpoint of the influence of the dimensions of the structural components on them. Analytical dependences of the governing relations of the mechanics of a deformable rigid body, which allow for the influence of the applied stresses, the structure, and the temperature on the rate of superplastic deformation (SPD) and enable one to calculate the shear viscosity and the rheological dependences of SPD for deformable aluminum alloys AMg4 and AMg6 with a prepared ultrafine‐grained structure, have been given.

DYNAMIC CUTTING OF AMg6 ALUMINUM ALLOY CASINGS OF WARHEAD CONES

The relation between the cutting length of 9E-1028 warhead casings made of an AMg6 aluminum alloy 1.0 mm thick and the initial speed of an explosive-propelled massive knife was obtained experimentally. These data were used to determine the cutting force. Mean stresses on the knife–casing contact surface corresponding to this force are comparable with the yield strength of an AMg6 alloy.