Search

In this paper, an attempt is made to characterize the in-house development of aluminium copper alloy (duralumin). Further the investigation moves to examine the effect of grain refiner process on microstructure of duralumin. The experimental process involves the casting process of duralumin with pure aluminium and master alloy (Al-40 wt%Cu.). For grain refinement of the duralumin, different fraction of Al-3Ti-0.15C grain refiner was added to the duralumin. The results highlight that the grain refiner with addition of 0.6% Al-3Ti-0.15C will be resulted in the reduction of grain size of duralumin.

Data for solubility of hydrogen in binary liquid aluminium alloys have been reanalysed by normalising alloy hydrogen solubility data with that for pure aluminium reported in the same study. This me...

The mechanism of the material destruction under discharge pulses and material removal mechanism based on the thermochemical nature of the electrical erosion during electrical discharge machining of conductive materials were researched. The experiments were conducted for two structural materials used in the aerospace industry, namely austenite anticorrosion X10CrNiTi18-10 (12kH18N10T) steel and 2024 (D16) duralumin, machined by a brass tool of 0.25 mm in diameter in a deionized water medium. The optimized wire electrical discharge machining factors, measured discharge gaps (recommended offset is 170–175 µm and 195–199 µm, respectively), X-ray photoelectron spectroscopy for both types of materials are reported. Elemental analysis showed the presence of metallic Zn, CuO, iron oxides, chromium oxides, and 58.07% carbides (precipitation and normal atmospheric contamination) for steel and the presence of metallic Zn, CuO, ZnO, aluminum oxide, and 40.37% carbides (contamination) for duralumin. For the first time, calculating the thermochemistry parameters for reactions of Zn(OH)2, ZnO, and NiO formation was produced. The ability of Ni of chrome–nickel steel to interact with Zn of brass electrode was thermochemically proved. The standard enthalpy of the Ni5Zn21 intermetallic compound formation (erosion dust) ΔH0298 is −225.96 kJ/mol, the entropy of the crystalline phase Scint is 424.64 J/(mol·K).

In recent days, the aluminium related metal matrix was an essential role in manufacturing sectors due to its substance properties. In the present topic, describes the duralumin composite was manufactured through stir casting method. The Tantalum Carbide (TaC) was a reinforcement material used to duralumin MMC. The substance composition was studied through Energy Dispersive Analysis of X-rays (EDAX). The machinability characteristics were analyzed through Spark Erosion Process (SEP). The Material Subtraction Rate (MSR) was measured by the variation of current, pulse on time and voltage. The parametric optimization was achieved by Taguchi technique and its effects were calculated by variance test.

Production of high-quality semi-finished product from aluminum wrought alloys for subsequent deformation (rolling, stamping or pressing) is provides by obtaining the initial defect-free cast billet. The level of mechanical properties of alloys in the cast and heat-treated state is determined mainly by the internal structure of the grains, therefore one of the main parameters affecting the quality of the cast billet for subsequent plastic deformation is the manifestation of chemical heterogeneity of grains in the content of alloying elements or segregation. In this work, the alloys Al–Mn, Al–Mg and duralumin are investigated according to the method previously proposed by the same authors. These alloys can be conventionally chosen as model ones, to study the influence of the alloying character on the tendency of wrought aluminum alloys to manifest segregation effects in the cast state. Comparing the local content of alloying elements on the axes of dendrites with the brand composition of the alloys, a significant discrepancy was noted. This discrepancy is a measure of the inhomogeneity of the alloy. Taking the degree of deviation of the local composition from the brand as the value characterizing the degree of inhomogeneity of cast alloys Al–Mn, Al–Mg and duralumin, the values of the average homogeneity coefficient of these alloys are calculated. The homogeneity criterion, determined for the aluminum base of alloys, shows the dependence of the degree of homogeneity on the change in the nature of alloying and the content of alloying elements. Significant differences between the local content of alloying elements in the axes of the dendrites and the grade composition of the alloys were revealed.

The possibility of reinforcing the Al/Al2O3 laminated cermet matrix with metal rapidly solidified alloy fibers (steel, titanium, and aluminum), as well as discrete duralumin chips, is shown. The maximal reinforcing effect was attained when using titanium and steel fibers with their content of 20 and 10 vol %, respectively, due to the implementation of several energy-intensive destruction mechanisms. Reinforced composites are characterized by the following properties: ρ = 2.30–2.85 g/cm3, σbend = 180–250 MPa, K 1c = 7.5–15 MPa m1/2, and KCU = (18–35) × 103 J/m2. The Al/Al2O3–Ccoke.residue has ρ = 2.21–2.23 g/cm3 at a very low sliding friction coefficient of 0.17 (the counterbody is a ball made of steel ShKh-15 under a load of 1 N). The oxide-adhesion bond type, which makes it possible to remove spent grains from the grinding work zone and implement the self-sharpening mode, is formed for the “Al/Al2O3–fused alumina grains” composite. The material that contains kaolin fibers is ultra-light-weight ceramic insulation (0.25–0.5 g/cm3), λ = 0.07–0.2 W/(m K) in the 20–1000°C range. The material including alumina spherulites combines rather high hardness (σbend = 10–50 MPa) and porosity (42–52%) and has increased thermal stability due to the rapid elimination of the temperature gradient on structural elements having a micrometer-size cross section.

International audience; Precipitation in Duralumin, a historic quaternary alloy of the type: Al–Cu–Mg–Si, was never fully studied nor observed by current electron microscopy techniques. This article presents the full characterization and comparison of two alloys: a Duralumin (A-U4G) from the 1950s collected on a vintage aircraft and its modern equivalent: a 2017A alloy. The as-received and peak-aging states were analysed with DSC, SAXS and TEM advanced techniques. It is shown that old Duralumin and modern 2017A present a similar nanoprecipitation in the as-received state and behave similarly upon artificial aging. As opposed to what has been reported in the past, three types of precipitates participating in hardening were found upon aging: θ’-Al2Cu, Q’(Q)-AlCuMgSi and Ω-Al2Cu.

Aluminum alloys are very interesting witnesses of industrial and technical development. The first ever developed was Duralumin, a light metal with good mechanical properties. In the 1930s, the rise of nationalism stimulated research and development, generating various aluminum alloys. This work reports the comparison of two versions of aluminum alloys, which were found in collected parts of WWII crashed aircraft from four nations: a Messerschmitt Bf 109 (DE), a Dewoitine D.520 (FR), and a P-51 Mustang (USA) and an Avro Lancaster (United Kingdom). The first version of alloy with magnesium content below or equal to 1 wt.% and the second version with higher magnesium content (1.5 wt.%), were identified as respectively AlCuMg1, AlCuMg2 in Germany, Duralumin, Duralumin F.R. in France, Hiduminium DU Brand, Hiduminium 72 in the UK and 17S, 24S in the USA. This study uses a multiscale approach based on historical research complimented by laboratory analyses of materials directly collected on the crashed aircraft. It allows a comparison and a better knowledge of the alloys used in each nations: their chemical composition, designations, microstructure, and mechanical properties are investigated.

This paper describes a study concerning the inner turning of a piece of duralumin, using 6 values of the feed. The shapes and micro-geometry of the resulting chips have been observed experimentally and these are explained by the large deformations in the cutting area. The processed surfaces, both by enlarging them to a microscope and by measuring the roughness have been experimentally studied. Also, the sections of chips are analysed, giving the theoretical and real dimension values, also interpreted on the basis of the deformations in the cutting area. Also, values of roughness parameters are presented.

The purpose of this study is to examine the effect of peening on the fatigue life of a duralumin plate containing a hole with rounded edges. To this end, duralumin plates containing holes with rounded edges with a radius of 0.5 mm were treated by cavitation peening (CP) and shot peening (SP). Fatigue tests under uniaxial tensile loading were carried out to obtain the lifetime versus applied stress curves, i.e., the S - N curves. Then, the fractured surfaces were examined using SEM. Also, a combination of residual stress measurements with electro-chemical polishing was carried out to evaluate the compressive residual stress profile with respect to the depth into the wall surrounding the hole. The results showed that the lifetime of the CP specimen was almost 25 times larger than that of the as-machined one. The fatigue strength, also, was increased by 18% by cavitation peening. In contrast, shot peening reduced the lifetime, since this caused the formation of a roll over layer at the rounded edges, from which cracks due to high stress can initiate. The effect on the fatigue strength of a plate with a hole can be explained on the basis of whether or not roll over occurs and on the residual stress profile with respect to the depth from the surface surrounding the hole.

The article presents the results of tribological research into engineering polymers (POM, PEEK, PPS) cooperating in sliding motion with 316L steel and EN AW-2017A aluminium alloy in the presence of a liquid (water, hydraulic oil HLP68). This type of friction pair may occur in hydraulic systems (gear pumps, valves, etc.). For comparison, additionally, the results of tribological research carried out in dry friction conditions have been shown. In addition, the results of microscopic study of the sliding surfaces of polymeric materials have been presented. Analysis of the test results allows one to describe the processes of friction and wear of the studied sliding pairs.

A measuring system based on an eddy-current transformer permits the detection of defects in plates of duralumin and aluminum–magnesium alloys.

The present analysis emphasizes on optimization of pouring speed, stirring speed and pouring temperature for mechanical properties and machining properties of aluminium metal matrix composites. In Al6061 aluminium, alloy presence of Mg improves the wettability with SiCp. Precipitation hardening was also achieved; furthermore, the addition of 4 % Cu is more or less admired to duralumin that has precipitation hardening phenomenon when it is added above 560°C. Precipitation hardening prevents dislocation at the molecular level and improves the strength of the material. Five levels of pouring speeds and two types of material meant that matrix alloy and metal matrix composites [i.e. Al6061 + 4 % Cu and Al6061–4 % Cu–5 % SiCp-reinforced metal matrix composite processed using stir-casting technique] are under consideration as an input parameter. In the second experimentation, five levels of stirring speed and five levels of pouring temperatures at a constant pouring speed of 2.5 cm/s were considered as an input parameter throughout. Outputs are: hardness, impact strength and metal removal rate through electron discharge machining of metal matrix composites casting for each experiment. It ought to be over that metal that metal matrix composite is best in terms of hardness, impact strength and machining ability, compared to base matrix alloy in any respect of pouring speeds. The optimum worth of hardness, impact strength and higher metal removal rate is ascertained whether the pouring speed varies from 2 to 3 cm/s for metal matrix composite. It is inferred from the second section of the experiments that a pouring temperature range of 700–750 °C and 400–600 rpm stirring speed offers higher worth of mechanical [hardness and impact strength] and machining properties. The scanning electron micrographs [SEM] shows the result of pouring speeds, stirring speed and pouring temperature of metal matrix composites.

The effect of hydrogen embrittlement on the localized plastic deformation of aluminum alloy D1 was investigated. The studies were performed for the test samples of aluminum alloy subjected to electrolytic hydrogenation. It is found that the mechanical properties and localized plastic deformation parameters of aluminum alloy are affected adversely by hydrogen embrittlement. The hydrogenated counterpart of alloy has a lower degree of ductility relative to the original alloy; however, the plastic flow behavior of material remains virtually unaffected. The deformation diagrams were examined for the deformed samples of aluminum alloy. These are found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Ludwik-Holomon equation. Using digital speckle image technique, the local strain patterns were being registered for the original alloy D1 and the counterpart subjected to electrolytic hydrogenation for 100 h.

The paper presents investigations of the effect of hydrogen embrittlement on the plastic flow. The studies are performed for test samples of aluminum alloy subjected to electrolytic hydrogenation in a three-electrode electrochemical cell at a controlled constant cathode potential using the Digital Image Correlation method. Diagrams of localized plasticity wave propagation through the length of the sample under deformation have been obtained. The deformation diagrams are examined for the deformed samples of the aluminum alloy and also main parameters of localized plasticity patterns are determined. Using the scanning electron microscopy method, the changes in the fracture surface are investigated.

In order to demonstrate the advantages of cavitation peening, in which the impact due to cavitation bubbles collapsing is used to mechanically treat a surface, compared with shot peening, the fatigue lives of peened specimens comprising duralumin plates with open holes were evaluated. In the present experiment, cavitation bubbles were generated by injecting a high speed water jet into a water filled chamber, producing what is known as a cavitating jet. The specimens, which had either a chamfered or rounded edge hole, were treated by cavitation peening and shot peening, then tested using a tensile fatigue test. The fatigue life of the shot peened specimen was equal to or less than that of the as machined specimen, whereas cavitation peening extended the fatigue life. When the cavitating jet was injected in such a way that the cavitation bubbles collapsed at the wall surrounding the hole, the fatigue life at a maximum tensile stress, σ max , of 150 MPa was extended by more than a factor of ten. It was also demonstrated that cavitation peening introduced compressive residual stress of about 300 MPa into the wall surrounding the hole.

The compound process of hot stamping and solution quenching heat treatment (HFQ®) was utilized to fabricate hard aluminium fairing of high aspect ratio. A simulation model was established by MSC.Marc to optimize the shape and size of the blamk as well as the effects of process parameters, namely, initial temperature, stamping speed, blank holder force (BHF), on extreme final temperature and thickness distribution of formed component were investigated. The reliability of finite element simulation was proved by the hot stamping experiments with self-designed moulds under the optimize process parameters achieved by simulation results. The results indicated that the optimized blank is well deformed without flange wrinkle and broken round; the maximum cooling rate in quenching can inhibite the precipitation when the initial temperature ranges from 350 to 450℃; BHF effects dominated on thickness distribution and 10KN is the most reasonable value under the studied condition while the optimum stamping speed is 100mm•s-1. Compared with the thickness of the stamping trials and numerical simulation, the deviation is less than 3.6%. Furthermore, The desired mechanical property is achieved without significant inhomogeneity.

The existing process of 2A12 aluminium alloy piston is cutting completed by hot- drawing pole , as a material utilization rate less than 40%. In order to improve material utilization, cold-extrusion process is the reasonable choice, but only if solve the annealing before cold-extrusion, surface lubricated, the Parameter optimization of cold-extrusion and quenching process after extrusion. This research uses the DEFORM finite element analysis and a good effect in practical application is obtained to enhance the rate of more than 80% material utilization, scrap rate is less than 0.5%.

Nowadays, critical aircraft application demands high end performance of respective aerospace materials. Al–4.5 %Cu alloy known as duralumin have extensive application on spacecraft, as ring rolled and heat treated condition. However, behaviour of the same alloy at high temperature is always a thirst area to improve the understanding. This paper mainly focussed on the behaviour of duralumin alloy during hot tensile testing. Hot tensile testings were done at six different temperatures ranging from room temperature to 300 °C. Mechanical properties at various temperatures were measured and studied along with the microstructural changes at all experimental conditions. Thermodynamic software package FactSage simulation was employed to identify the precipitates expected to precipitate at high temperature. Important conclusions were drawn from both theoretical and experimental observations.

In this report, the aluminium metal matrix was reinforced with 1.5 wt. % of Al2O3 nano particles using non-contact cavitation method to prepare the metal matrix nano composite. Microstructural examination conducted on the samples revealed a uniform distribution of alumina particulates. Sliding wear behavior of the as-cast MMNC was studied in dry condition, under different test conditions by varying the load and the sliding velocity, with an unlubricated Multiple Tribo Tester. It was found that resistance to sliding wear improved considerably with the addition of alumina nano particles. Microscopic examinations of the worn out surfaces of pure Al, Al-alloy (duralumin) and MMNC reveal that the MMNC has greater resistance to sliding wear compared to pure aluminium and duralumin. Wear increases with increase in load and sliding velocity. Wear is more when load and speed are increased in steps. Delamination and abrasion are the dominating types of wear observed.

The effect of hydrogen embrittlement on the plastic flow of aluminum alloy D1 was investigated. The studies were performed for the test samples of aluminum alloy subjected to electrolytic hydrogenation in a three electrode electrochemical cell at a controlled constant cathode potential. It is found that the mechanical properties and plastic flow curves of aluminum alloy are affected adversely by hydrogen embrittlement. The hydrogenated counterpart of alloy has a lower degree of ductility relative to the original alloy. The deformation diagrams were examined for the deformed samples of aluminum alloy. These are found to show all the plastic flow stages: the linear, parabolic and pre-failure stages would occur for the respective values of the exponent n from the Ludwik-Holomon equation. Microhardness tests were performed for as-treated aluminum alloy D1. Using scanning electron microscopy method, the changes in the fracture surface were investigated.

Brush plating has been an important technology for the mending of the scratched surface of the engineering parts in recent years. The process for brush plating mending of deeply scratched surface of the parts made by 7A04 super-duralumin alloy is introduced in this article. The merits of the brush plating mending technology of 7A04 super-duralumin alloy are discussed.

The metal matrix composite (MMC), despite of its high stiffness, strength, corrosion resistance, wear resistance, non-react with chemicals and so many other tailored qualities which are never obtained in alloy of metals, has limited utilization due to the high cost of fabrication. In this study, a modest attempt has been made to find out the process parameters at which best mechanical properties of Al6061, 4% Cu and reinforced 5% SiCP ceramic MMC can be obtained. The addition of 4% Cu in Al6061 is more or less comparable to the composition duralumin, which are widely used in aerospace applications. SiCP is hard and has linear thermal expansion at high temperature. With reinforcement of SiCP in Al6061-Cu alloy, it can be postulated that hardness of MMC retains at high temperature applications. An analysis of Variance (ANOVA) and linear regression was used for analysis of data with the help of SPSS (Version-17.0). Independent parameters are five levels of pouring rates (1.5 cm/s, 2.0 cm/s, 2.5 cm/s, 3.0 cm/s and 3.5 cm/s), and material type (Al6061 + 4% Cu alloy and Al6061 + 4% Cu, reinforced 5% SiCp MMC processed using stir casting technique) and dependent parameters are hardness and impact strength material removal rates of workpiece. It is found that at different pouring rates material hardness and impact strength of workpiece are highly significant but the material removal rate of workpiece is having no significance value. At pouring rate of 2.5 cm/s and 700℃ ± 5℃ pouring temperature, optimum values of hardness and impact strength are observed as compared to other values of pouring rates (1.5 cm/s, 2.0 cm/s, 3.0 cm/s and 3.5 cm/s). Material Removal rate for work pieces of Al6061 + 4% Cu alloy is less as compared to MMC. So it can be concluded that MMC has better machining ability compared to Al6061 + 4% Cu alloy. Material removal rate of Al6061 + 4% Cu, reinforced 5% SiCP MMC has maximum values at 1.5 cm/s pouring rate compared to 2.0 cm/s, 2.5 cm/s, 3.0 cm/s and 3.5 cm/s pouring rates. With reinforcement of 5% SiC trend of mechanical properties is same, but the hardness and impact strength of MMCs are increased by 25% and 20% respectively. Also it is observed from scanning electron microscopy (SEM) that at pouring rate 2.5 cm/s a better homogeneity can be obtained.

It was demonstrated in the present paper that cavitation peening which is one of the mechanical surface modification technique can suppress fatigue crack propagation in duralumin. The impacts produced when cavitation bubble collapses can be utilised for the mechanical surface modification technique in the same way as laser peening and shot peening, which is called “cavitation peening”. Cavitation peening employing a cavitating jet in water was used to treat the specimen made of duralumin Japanese Industrial Standards JIS A2017-T3. After introducing a notch, fatigue test was conducted by a load-controlled plate bending fatigue tester, which has been originally developed. The fatigue crack propagation behavior was evaluated and the relationship between the fatigue crack propagation rate versus stress intensity factor range was obtained. From the results, the fatigue crack propagation rate was drastically reduced by cavitation peening and the fatigue life of duralumin plate was extended 4.2 times by cavitation peening. In addition, the fatigue crack propagation can be suppressed by 88% in the stable crack propagation stage by cavitation peening.

Al–Mg–Si alloys were irradiated with 5.4 MeV Al ions, 7.3 MeV Fe ions, 10 MeV I ions, and 16 MeV Au ions at room temperature and the Vickers microhardness was measured. The hardness of Al–Mg–Si alloys increases with increasing the ion fluence. In a viewpoint of ion fluence, hardness change of the Al alloys is different by the kind of irradiating ions. But, in a viewpoint of the density of elastically deposited energy, the effect of the four kinds of them on hardness is almost the same. This result means that the effect of irradiation on hardness of Al–Mg–Si alloys is dominated by the elastically deposited energy. The microstructure of the ion-irradiated specimens were investigated by means of three-dimensional atom probe (3DAP). The experimental result was compared with the microstructure and the hardness for thermally aged specimens. We also discuss the difference in ion-irradiation induced change in hardness between Al–Mg–Si alloys and Al–Cu–Mg alloys (duralumin).

Design an experimental method which can test the strength change of materials under the ultrahigh pressure, and a set of experimental data about the LY12 duralumin alloys materials yield strength and tensile strength are gained under the different ultrahigh pressure environment. The analysis result shows the strength of LY12 duralumin alloys will enhance. Because of effect of ultrahigh pressure, both yield strength and tensile strength increment of materials will approximately increase linearly. Beyond this, the method that can effectively build ultrahigh pressure environment has guidance significance for a real project.

Using A-TIG to welding thick plate duralumin alloy and designing rationally welding processing for Y groove butt plates welding of duralumin alloy. Using repeated measurements of dot to get transverse and vertical welding deformation under different current of A-TIG after welding. This paper analyzed the influence of different current on welding deformation and the features of A-TIG welding deformation. The result showed that transverse deformation was the uniformity along weld direction but was not uniform along weld vertical direction. Transverse deformation was larger when it was nearer to weld. Vertical deformation of middle position of weld was smaller than the part of arc starting and arc suppression. The result also showed that the deformation increased as the current increased.

This paper presents the results of a study undertaken to investigate the passive force and cutting torque during the milling of carbon fiber reinforced plastics saturated with epoxy resin and two aluminum alloys: AlSi21CuNi (AK 20) and 7075 (PA 9). The milling process was conducted using end mills with diamond inserts. The machining parameters were changed equally for each material as a result of which the passive force and cutting torque during the milling of these materials could be compared.

Pure metal microspecimens have been found to exhibit strong size dependence of strength, but alloyed counterparts with a much refined microstructural length scale due to the precipitates present are as yet unknown. Here, compression tests on duralumin (aluminum 2025 alloy) micropillars reveal a much weaker size dependence of strength compared to pure Al, indicating the predominance of the internal length scale in determining strength. Creep is also significant in duralumin, probably due to the viscous overcoming of obstacles during deformation.

Comparative study of laser welding method has been carried out at four different methods of welding in Sm-Co system on two types of substrates: stainless steel and duralumin and at two types of argon gas flow in the place of melting. The comparison of compositions and magnetic properties of welded coatings has been done for all formed samples. It was established that SmCo 8.5 compound conserves only after laser welding of SmCo 8.5 tablets with additional contribution of oxides that results to strongly decrease of saturation magnetization and coercivity as compared with SmCo 8.5 films. In the case of the standard argon gas flow and using of Sm and Co powders the quick melting of the stainless steel substrate surface occurs that results to strong diffusion of transition metals to the welded layer and formation of Sm-based, noncrystalline alloy with only two crystalline phases (Co 0.72 Fe 0.28 and Co), which demonstrate soft ferromagnetic properties. The formation of Sm-Co chemical compound is blocked when the Co welding carried out after Sm welding due to formation of Sm oxides on the welding surface. In the conditions of a stable argon atmosphere around the sample the pure Co and Sm crystals have been formed with weak ferromagnetic properties.

Wear behavior is influential to improve friction drive and wear lifespan of actuators or motors, which work at an elliptical locus vibration. Sliding wear tests of metallic friction pairs are conducted by a laboratory rig of ultrasonic vibration. Surfaces of the different metallic sliders are characterized using surface roughness, Abbott curves and fractal dimension. Results show that surface roughness is reduced to varying degrees in the metallic sliders due to ultrasonic polishing and/or micro-rolling effect. Variations in the fractal dimensions of contact surfaces are consistent with that of surface roughness. Wear traces demonstrate that plastic deformation and cracking are the primary failure modes. Where the driving tip on the slider is in intermittent contact followed by impact effects, ripples of 3~5 μm traces suggest the occurrence of fretting in duralumin sliders. Nodular cast iron showed a favorable performance during running of ultrasonic motor, exhibiting a stable output performance and durable wear life.

The effect of the microstructures observed in different zones of friction stir welded duralumin on the mechanical properties of the alloy is investigated. A dynamic boundary-value problem represented in terms of the plane strain is solved numerically by the finite-difference method. A constitutive model accounting for the elastic-plastic behavior of the material experiencing isotropic strain hardening is built. A fracture criterion allowing for crack nucleation and growth in local regions of maximum equivalent plastic strains is formulated. The disordered polycrystalline microstructure observed in the base material and in the nugget is found to provide a lower strength as compared to the ordered lamellar microstructure of the material in the thermo-mechanically affected zone on the advancing side of the weld.

Superconducting compound Nb3Al was obtained as a result of thermal treatment of triple-layered Nb/Al/Nb and multilayered Nb/Al ribbons. The effect of copper on superconducting characteristics of Nb3/Al diffusive layers formed in Nb/AlCu/Nb composite was studied. The possibility of producing the β (Nb3Al) phase via diffusion at temperatures below 1000°C was shown. However, superconducting properties of these ribbons were low. The best superonducting properties had multilayered niobium or duralumin ribbons after heating at 1700°C for a few seconds.

Brush plating has been an important technology for mending the scratched surface of the engineering parts in recent years. The duralumin alloy is common used structural material. The process for brush plating mending of deeply scratched surface of the parts made by LY11 duralumin alloy is introduced, the technologic methods of LY11 duralumin alloy are studied and analyzed, the merits of the brush plating mending technology of LY11 duralumin alloy are discussed in this article.

Porosity in cast metals often leads to cracking of components due to stress concentration and leakage, and as the result, the castings need be repaired or rejected. Disharmony in casting process was resulting in porosity. Prediction of porosity in the casting is necessary as a step to avoid the waste products and reduce costs. But to ensure whether these predictions are accurate and precise, it is still necessary to validate the test trials and testing. This paper aims to provide early information when, where, and how large a defect occurs in particular foundry casting porosity on duralumin. The analytical study of porosity formation based analytic equilibrium wt% of element, the behavior of the thermodynamic, hydrodynamic, and rules of metallurgical on vacuum casting of duralumin. Experiments as a validation study are conducted by duralumin remelting on stainless-steel bowl in a vacuum casting furnace. Analytical simulation and experiments of the casting that has been vacuumed by melting 10 cmHg pressures higher than the pressure solidification, and duralumin melt is poured automatically into permanent mold carbon steel. In the study cast duralumin created five different thicknesses. Both these studies assume the addition of copper (2.5%, 3.0%, 3.5 %, 4.0%, and 4.5% Cu) and vacuum pressure (76, 50, 40, cmHg), as independent variables, while dependent variable in the studies is porosity characteristics, which includes morphology, number and dimensions of the porosity. Optical emission spectrometry test, Reynold's and Niyama numbers, Sievert's law, Archimedes' principle (Pycnometry and Straube-Pfeiffer tests), and Eichenauer equation are instruments which are used to determine the characterization of duralumin casting porosity. Duralumin ingots remelting process was performed by the control pressure (p1) and temperature (T1). Vacuuming process performed after the smelting room temperature reaches 600 °C. Once melted, it followed by duralumin into a permanent mold (p2, T2). As a control parameter is the height of pouring (7 cm), pour temperature and mold temperature respectively at 750 °C and 300 °C. The porosity characteristics studies of two models produce two types of porosity (gas and shrinkage), the quantity dimension and porosity, and distribution of porosity in the cast duralumin.

For modeling the space dust and debris effect on flying vehicles, an investigation of the low-velocity impact of corundum and tungsten powders, accelerated by explosion, with particle size up to 50 microns on steel and duralumin targets was carried out. Also studied was the impact of sewing needles against metal and dielectric barriers, antimeteor shield models, and duralumin containers with hard materials, gunpowder, and explosives. At impact of powders at velocities of up to 2 km/s and needles at a velocity of up to 0.5 km/s against metals, the channels arose with lengths greater than 100 and 50 diameters of a striker. At impact of needles, the containers with hard explosive materials were destroyed because of ignition of their contents, and containers with plastic explosive were punched through, and no burning occurred. The energy, released at destruction of plexiglas blocks and containers with hard materials, many times exceeded the impact energy due to release of the elastic energy stored in them.

Aluminium is a fairly recent metal (XIXth century). Investigations of its alloys developed in a military-industrial context. Duralumin was, thus, discovered at the beginning of the last century in Prussian Germany by the Metallurgist Engineer Alfred Wilm (1869 – 1937) who had been explicitly mandated to look for an improved aluminium alloy in a military-owned research centre located in Neubabelsberg, just south-west of Berlin. The name Duralumin is as much due to the fact that it is hard as to the fact it has first been industrially produced in Duren. International connections, as well as harsh competition, accompanied the first research on this alloy in the beginning of the twentieth century.

Brush plating has been an important technology for mending the scratched surface of the engineering parts in recent years. The duralumin alloy is common used structural material. The process for brush plating mending of deeply scratched surface of the parts made by 2A11 duralumin alloy is introduced, the technologic methods of 2A11 duralumin alloy are studied and analysed, the merits of the brush plating mending technology of 2A11 duralumin alloy are discussed in this article.

Using a model of a duralumin alloy, we have studied the inhibiting efficiency of strontium chromate and a composition of phosphate and calcium-containing pigments in slightly acid rain solution. We have established that the nonchromate composition decreases the efficiency of cathodic processes on the intermetallic part of the model better than the chromate inhibitor due to the formation of a stable adsorption film containing zinc and aluminum phosphates. The proposed composition can serve as a promising substitute for toxic chromate pigments in anticorrosive paint-and-lacquer coatings on duralumin alloys.

Through intensive analysis of the tensile stress-strain curves of a variety of steel sheets over a wide range of strain rates on the order of 10-2 ∼103 s-1 obtained by using the Sensing Block Type High Speed Material Testing System, it was confirmed that the newly-partially extended constitutive model (Tanimura-Mimura Model) is useful to simulate the dynamic stress-strain curves for the entire range of deformation reaching as far as fracture over the wide strain rate range, as long as the quasi-static stress-strain curve of the material concerned is only known in advance. Dynamic tensile properties, over the wide strain rate range and the entire strain region reaching the true fracture strain, of ten kinds of aluminum alloys, which compose of a wide strength level from a commercial pure aluminum to the extra super duralumin are systematically studied. It was cleared that the aluminum alloys belonging to the one group exhibit the positive strain rate sensitivity and the aluminum alloys belonging to another group exhibit the negative sensitivity or almost non sensitivity. It was found that the values of the true fracture strain ef are substantially not affected by the strain rates, for all the tested aluminum alloys, and are closely related to the values of the tensile strength σB whose values are obtained by the quasi-static nominal tensile stress-strain curves.