D16 Aluminum Alloy Research Articles

Wear-resistant oxide coatings on aluminum alloy formed in borate and silicate aqueous electrolytes by plasma electrolytic oxidation

There are several methods known of formation of wear-resistant oxide coatings on articles made of aluminum alloys by the method of plasma electrolytic oxidation (PEO), for example, in silicate and borate aqueous electrolytes. In the present work, a comparison of characteristics of PEO coatings obtained on AMg5 and D16 aluminum alloys in the bipolar mode by these two methods, as well as in mixed borate–silicate electrolytes, has been performed.

ОПЫТ РАЗРАБОТКИ И ПРОИЗВОДСТВА СТАНДАРТНЫХ ОБРАЗЦОВ СОСТАВА АЛЮМИНИЕВОГО СПЛАВА Д16

ОПЫТ РАЗРАБОТКИ И ПРОИЗВОДСТВА СТАНДАРТНЫХ ОБРАЗЦОВ СОСТАВА АЛЮМИНИЕВОГО СПЛАВА Д16

Физико-механические свойства стыковых соединений тонколистового алюминиевого сплава Д16, полученных сваркой трением с перемешиванием

Физико-механические свойства стыковых соединений тонколистового алюминиевого сплава Д16, полученных сваркой трением с перемешиванием

Physico-mechanical properties of thin-sheet aluminum alloy D16 butt joints produced by friction stir welding

Physico-mechanical properties of thin-sheet aluminum alloy D16 butt joints produced by friction stir welding

Electrochemical Dispersion of Aluminum Alloys in an Aqueous Sodium Hydroxide Solution

Results of experiments on the kinetics of hydrogen generation by electrochemical dispersion of an aluminum alloy D16 in an aqueous solution of sodium hydroxide under alternating (AC) electric current are provided. It was found that the rate of hydrogen evolution under alternating electric current is significantly greater than the rate of hydrogen evolution in a reaction without the application of an electric current. The use of an alternating current produces Al(OH)3 powders with more highly disperse particles.

Influence of Zr on intergranular corrosion of cast and cryorolled D16 aluminum alloy

Effects of severe plastic deformation by isothermal сryorolling at a temperature of liquid nitrogen with a strain of e~2 and subsequent natural and artificial aging on the evolution of structure, hardness and resistance to intergranular corrosion (IGC) of the preliminary quenched D16 aluminum alloys of conventional and Zr modified compositions, were investigated. It was found that the natural aging of alloys had slight effect on corrosion resistance due to formation of Guinier-Preston-Bagaratsky zones. Because of their coherency to matrix, difference in their electrochemical potential was low, causing slight effect on corrosion resistance. Artificial aging to the maximum strength, performed at 190ºC for 12 hrs in accordance to conventional T1 route, in both rolled and non-rolled states of the alloys of both compositions led to strong decrease of IGC resistance due to precipitation of strengthening phases instead of zones, formed at natural aging. Modification of the alloy composition, via substitution of Mn by twice less amounts of Zr and decrease in impurity contents, had a minor influence on its structure and hardness in the initial and rolled conditions. However, it significantly enhanced corrosion resistance, reducing its depth and intensity, in both naturally and artificially aged conditions studied. It was concluded that the main factors, determining the alloy microstructure changes, mechanical and corrosion behavior, are the volume fraction and morphology, and spatial distribution of second phases - excess phases and precipitates.

Production of Hydrogen and Aluminum Hydroxide by Electrochemical Dispersion of Aluminum Alloys D16 in Sodium Hydroxide Aqueous Solution

Kinetics experimental results of the interaction of an aluminum alloy D16 with a sodium hydroxide aqueous solution under the alternating electric current are presented. It is stated that the reaction rate under the AC is much larger than the reaction rate without applying an electric current. The use of an alternating electric current makes it possible to obtain smaller particles of Al(OH)3 with a narrower particle size distribution range.

Effect of electrical parameters on the efficiency of the process of microarc oxidation of D69 aluminium alloy

Results of investigations of the effect of energy parameters on the process of micro-oxidation and the quality of produced oxidised coatings on the D16 aluminium alloy are presented. The coatings formed in oxidation in different working conditions of the power source with the capacitance regulation of power are compared. The microstructure of the surface of the specimens with the coatings produced in microarc oxidation in three sets of conditions is shown.

Determination of welding speed in electron beam welding of thick components with continuous penetration

An improved method for calculating the minimum permissible electron beam welding (EBW) speed with continuous penetration is described. Calculations are carried out to construct nomograms for determining the welding speed in relation to the thickness of the welded joint and the width of the vapour-gas channel for 40Kh13 steel, 5V titanium alloy and D16 aluminium alloy. To confirm the efficiency of the proposed method, the results of experiments with EBW with continuous penetration at different welding speeds are presented.

Fatigue life predictions for riveted lap joints

A semi-empirical fatigue life prediction model for riveted lap joints representative of the aircraft fuselage skin connections is developed. The effect of the interference fit between the rivet and the hole is taken into account utilizing fatigue test results for 2024-T3 Alclad aluminium alloy coupons with an open and filled hole. The effect of contact surface friction is considered based on comparisons between the fatigue lives of lap joints from 2024-T3 Alclad sheets and universal rivets with the Alclad contact surface and the fatigue lives of similar joints with the Teflon interfoil which eliminates friction between the sheets. Dependencies between coefficients incorporated into the model to account for the above mentioned effects and several quantities related to the amount of rivet squeezing, and thus representative of the riveting process, are provided. The fatigue life is assumed to be controlled by the local stress amplitude at the critical location of a joint. Analyses of the fatigue test results for the 2024-T3 riveted joints prove that the local stress estimated using the superposition approach can adequately represent the combined effect of the applied loading, interference between the rivet and the hole and faying surface friction condition on the fatigue life. The adequacy of the proposed model is substantiated by a good agreement between the fatigue lives predicted and observed for lap joints from D16 aluminium alloy sheets and round head rivets.

Еволюція структурного стану та мікротвердости поверхні алюмінійового стопу Д16 внаслідок ультразвукового ударного оброблення в різних атмосферах

Еволюція структурного стану та мікротвердости поверхні алюмінійового стопу Д16 внаслідок ультразвукового ударного оброблення в різних атмосферах

The effect of the electron beam welding speed on the chemical composition, structure and properties of welded joints in D16 aluminium alloy

Experiments were carried out to investigate the effect of electron beam welding speed in the range 20–120 m/h on the properties of welded joints in 20-mm-thick plates of D16 alloy. The distribution of magnesium in the cross section of welded joints in dependence on the welding speed was determined. The structure of the welded joints was investigated by optical and electron microscopy. The hardness in different zones of the welded joints after welding and different types of heat treatment was measured. The relationship between the chemical composition, structure and mechanical properties of the welded joints produced at different welding speeds was determined.

Particle velocity non-uniformity and steady-wave propagation

A constitutive equation grounded in dislocation dynamics is shown to be incapable of describing the propagation of shock fronts in solids. Shock wave experiments and theoretical investigations motivate an additional collective mechanism of stress relaxation that should be incorporated into the model through the standard deviation of the particle velocity, which is found to be proportional to the strain rate. In this case, the governing equation system results in a second-order differential equation of square non-linearity. Solution to this equation and calculations for D16 aluminum alloy show a more precise coincidence of the theoretical and experimental velocity profiles.

ELECTRIC CURRENT EFFECT ON ALUMINUM ALLOY D16 DISPERSION IN SODIUM HYDROXIDE AQUEOUS SOLUTION

The experimental results on aluminum alloy D16 kinetics interaction with the aqueous solution of sodium hydroxide under the action of an alternating electric current. It was found that the reaction rate under an alternating electric current is significantly greater than the reaction rate without an electric current application. The use of electrical current allows to obtain Al(OH) 3 particles with a smaller size and a narrower range of particle distribution by sizes.

Fatigue Surface Crack Growth in Aluminum Alloys under Different Temperatures

The variation of crack growth behavior is studied under cyclic axial tension fatigue loading for the different temperatures conditions. The subject for studies is cylindrical hollow specimens of B95 and D16 aluminum alloys with semi-elliptical surface cracks. By experimental studies for considered temperature conditions the relations between the crack sizes on the free surface of specimen, crack opening displacements (COD), crack growth rate and aspect ratio were obtained. These relationships are useful for automation of experimental studies of surface crack growth. For the same specimen configuration and the different crack front position as a function of cyclic tension loading and temperatures conditions, the following constraint parameters were analyzed, namely, the non-singular T-stress, Tz -factor and the stress triaxiality parameter h in the 3D series of elastic-plastic computations. The governing parameter of the elastic-plastic stress fields In-factor distributions along various crack fronts was also determined from numerical calculations. The plastic stress intensity factor (SIF) approach was applied to the fatigue crack growth on the free surface of the hollow specimens as well as the deepest point of the semi-elliptical surface crack front. As result principal particularities of the fatigue surface crack growth rate as a function of temperature conditions are established.

Nanostructuring of 2xxx Aluminum Alloy under Cryorolling to High Strains

The structure transformations in the D16 (2024) aluminum alloy caused by isothermal rolling with effective strain up to e ~3.5 at a temperature of liquid nitrogen were investigated. It is shown that under straining to e ~2.0 the dislocation structure containing cells of the nanometric size is formed. At higher strains the dynamic recovery and continuous recrystallization result in the development of a mixed nano(sub) grain structure, which after e ~3.5 is characterized by the size and volume fraction of grains ~ 150 nm and 40-45%, respectively. Nature of the alloy structure transformations is discussed.

Study of wire tool-electrode behavior during electrical discharge machining by vibroacoustic monitoring

In the current study, the full research of wire electrode behavior during electrical discharge machining is presented. The analysis of the work preparation processes gave a possibility to clarify the main parameters (factors) influencing on the final characterization of the obtained object. For the experiments, the system MACHINE-TOOL-WORKPIECE was established. The system was equipped by vibro-acoustic accelerometers to register the signals during processing. Processing of two work pieces from stainless steel 12Kh18N10T (analogue AISI 321) and aluminum alloy D16 gave the characterization of the material behavior. Further, the analysis of SEM pictures gave the important data about the character of wire tool wear during processing. The two main natures of the wire tool wear were recognized. The scheme of the wire tool wear for rough and finish cuttings was developed to demonstrate the results of the research.

Surface Crack Growth Rate under Tension and Bending in Aluminum Alloys and Steel

Fatigue surface crack growth is studied using FE-analysis and experiments for aluminum alloy D16 and low carbon steel under tension and bending. The subject for the study is central notched specimens with external semi-elliptical surface crack.Crack growth rate was determined on precracked specimens under tension and three point bend loadings. As experimental result the crack length increment on the specimen surface and crack edges opening displacement were obtained. A relationship between the crack form geometry and a number of loading cycles was obtained during tests by beach marks produced on each specimen.For the experimental surface crack paths in tested specimens the governing parameter for the 3D-fields of the stresses and strains at the crack tip in the form of In-integral was calculated by finite element analysis along semi-elliptical crack front. The governing parameter of the elastic-plastic stress fields In-integral was used as the foundation of the elastic-plastic stress intensity factor. The plastic stress intensity factor approach was applied to the fatigue crack growth on the free surface of the specimens and in the deepest point of the semi-elliptical surface crack front.A significant influence of material properties and loading type on crack growth rate characteristics was established in the present study.The experimental and numerical results of the present study shows that the elastic-plastic stress intensity factor, which is sensitive to elastic-plastic material properties, is attractive for fatigue crack growth rate characterization.

Dynamics of formation of low-angle tilt boundaries in metals and alloys at high loading rates

A computer model has been developed in which the process of formation of low-angle tilt boundaries and fragmentation of initial subgrains during shock loading of metals and alloys is clearly demonstrated by the of two-dimensional discrete dislocation–disclination dynamics method. The formation and evolution of such grains proceeds under the action of an external stress and the stress field of grain boundary disclinations distributed on the subgrain boundaries. With the D16 aluminum alloy as an example, three cases of fragmented structures formed in accordance with the initial configuration of the disclination ensemble have been considered for a dipole, quadrupole, and arbitrary octupole of wedge disclinations. It has been shown that, in all these cases, the formation of a stable fragmented structure requires a stress of ~0.5 GPa and time of 10 ns. The main results of computer simulation (the finite form of a fragmented structure, typical level of applied stress, and small fragmentation time) agree well with known experimental results on shock compression of the D16 aluminum alloy.

Mechanical properties of a metallic composite material based on an aluminum alloy reinforced by dispersed silicon carbide particles

The mechanical properties of a composite material with a matrix of aluminum alloy D16 reinforced with dispersed silicon carbide particles have been studied. The physicomechanical properties (density, elastic modulus, ultimate tensile strength, and limiting strains) of the composite material with various filler contents are determined experimentally. The experimental results are compared to the results of a theoretical simulation obtained using elastic and elastoplastic models of the composite material. The experimental and the calculated mechanical properties of the composite material with the volume content of the filler up to 30% agree well with each other.