Aluminum-magnesium Alloy Research Articles

The effect of FSW parameters on the macro/micro-galvanic corrosion of the dissimilar joint between AZ31 and AA5052

In this study, dissimilar friction stir welding was performed between AA5052 aluminium and AZ31 magnesium alloys using a variety of parameters. The results revealed that the optimal range of welding parameter is between 20 and 38 rpm/mm.min−1 (the ratio of rotation speed to travel speed). The findings of the X-ray diffraction and Micro-hardness tests on the stir zone indicated that when the rotation speed is increased, it leads to the formation of intermetallic compounds such as Al12Mg17 and Al3Mg2. The polarization test was used to assess the corrosion rate in various zones. The corrosion rate in the stir zone is higher than in other zones due to macro-galvanic couple between Al and Mg. Additionally, the corrosion rate in the stir zone of sample welded at highest rotation speed of 750 rpm is 1.6 mA cm−2, which is nearly 2.24 times higher than the corrosion rate in other samples. That is attributed to the micro-galvanic coupling of intermetallic compounds (cathode) to the matrix (anode), as well as the macro-galvanic coupling of AA5052 aluminium to AZ31 magnesium alloys.

Investigation of A New Type of Aluminum–Magnesium Alloy with Bismuth Additions Subjected to Thermomechanical Heat Treatment

Investigation of A New Type of Aluminum–Magnesium Alloy with Bismuth Additions Subjected to Thermomechanical Heat Treatment

Novel Approach to Prepare Magnesium and Mg-Al Alloy from Magnesia by Using the Closed Microwave Aluminothermic Method

Herein, we report a novel approach to obtaining magnesium and nanocrystal Mg-Al alloy from magnesia using a closed microwave aluminothermic method in order to solve the problems of high energy consumption, high pollution, and low productivity in the process of magnesium and its alloy production. The main idea of the paper is to design a technique for the preparation of magnesium–aluminum alloy during the reduction process of MgO directly under atmospheric pressure. Based on this experimental idea, we have established a closed microwave aluminothermic reduction reactor. The great advantage of the reaction device is that it can make the reaction material heat up quickly to the reaction temperature in the microwave heating process and produce high-pressure magnesium vapor, which reacts with aluminum dramatically to form Mg-Al alloy under microwave irradiation. By the calculation of the electromagnetic field of the reaction device and sample using ANSYS electronics desktop 2018, the optimum microwave heating conditions for samples have been established. Based on the calculation results, we demonstrate that magnesium and its alloy are prepared successfully by using this method. In addition, the reduction rate of MgO is greatly improved, which is higher up to 79.97 Wt% when the reduction time is 30 min, at 1273 K, and the Mg2Al3 and MgAl alloy is formed during the reduction process as well. Moreover, the formation mechanism of Mg-Al alloy during the reduction process under microwave irradiation was discussed further. Our findings could provide a new approach, insights, and research directions to obtain magnesium and Mg-Al alloy directly from magnesia under normal pressure.

A double molten pool laser welding process for joining magnesium alloys and aluminum alloys: The process, microstructure and mechanical properties of joints

In this study, AZ91/6061 dissimilar metal joints were successfully manufactured using double molten pool laser welding, and the process, microstructure, and mechanical properties of these joints were investigated. During welding, two laser beams irradiate the base metal on two sides, forming two independent molten pools with a Ni interlayer; thus, the heat input of the weld on both sides can be individually optimized according to the thermophysical properties of Mg and Al alloys. Owing to the physical isolation of the Ni interlayer, the generation of extremely hard and brittle Mg–Al intermetallic compounds is completely inhibited. The microstructure of the Mg side weld metal comprised Mg2Ni, α-Mg, (α-Mg+Mg2Ni) eutectic structures, and dispersed Mg3AlNi2. The microstructure of the Al side weld metal comprised AlNi3, Al3Ni2, Al3Ni, α-Al, and (α-Al+ Al3Ni) eutectic structures, which were the weakest zone of the joints. The optimal welding parameters were 1.0 m/min and 1300 W on the Mg side and 0.6 m/min and 1200 W on the Al side. Under these parameters, the mean microhardness of the Al side weld was significantly higher than that of the Mg side weld, and the average tensile strength of the AZ91/6061 joint was 83.58 MPa. Fractures occurred in the Al side weld metal by cleavage fracture.

Improved barrier effect of hierarchical micro-nano precipitate framework in magnesium-aluminum alloy for corrosion mitigation

The galvanic effect of second phases in Mg alloys often does harm to corrosion resistance. Here, a hierarchal micro-nano β phase framework is proposed to improve the barrier effect of the second phase in high-aluminum-containing Mg-Al alloy, which can be achieved through facile heat treatment. Compared to pristine and solid-solution-processed β phases, this designed β phase framework effectively mitigates the corrosion in 0.6 M NaCl solution because of the formation of a brick-and-mortar structured corrosion product layer.

Grain Refinement of Aluminum and Aluminum Alloys by Sc and Zr

Rare earth elements and transition elements are widely used in aluminum alloys, magnesium alloys and copper alloys due to their unique microalloying effects. With regard to in-depth research on the grain refinement characteristics of rare earth elements and transition elements, the combination of grain refinement and microalloying in the master alloys has a great impact on the theories and technical research of refinement, and the broadening of the application field of master alloys. This paper first summarizes the grain refinement mechanisms and analyzes the effects of rare earth elements and transition elements on the grain refinement of aluminum and aluminum alloys, and summarizes the elements suitable for the preparation of Al-M master alloys and their refinement mechanism.

Warm and hot deformation behaviors and hot workability of an aluminum-magnesium alloy using artificial neural network

In this work, flow stress behavior, softening mechanisms and processing maps during deformation of aluminum-magnesium alloy i.e. AA5052, were investigated. Firstly, tensile tests were carried out in the range of room temperature up to 450 °C under different strain rates between 0.001 s-1 to 0.05 s-1. Then, neural network algorithms together with dynamic materials modeling were employed for determination of stain rate sensitivity parameter and processing maps under different working conditions. Moreover, the governing constitutive equations as well as the activation energies of dynamic strain aging and hot deformation were defined. Accordingly, the processing maps were developed for different strains of 0.15, 0.2 and 0.3. The alloy showed a higher resistance to flow instability at high temperatures i.e. temperature above 350 °C. Besides, the activation energy for dynamic strain aging was computed as 46.2 kJ/mole while the apparent activation energy for hot deformation was calculated about 192.1 kJ/mole. It has been inferred that the governing softening mechanism in temperatures ranging 250–400 °C could be dynamic recovery, however, by increasing deformation temperature and/or under low strain rates, dynamic recrystallization would be operative leading to higher resistance to flow localization.

Characterization of Aluminium-Magnesium (Al-Mg) Alloy Reinforced with Strontium (Sr) by Casting Technique

Aluminium-metal matrix composites (Al-MMCs) are quite attractive due to their low density, ability to be reinforced by precipitation, good corrosion resistance, high thermal and electrical conductivity, and high damping capacity. In this study, the aluminium-magnesium (Al-Mg) master alloy was reinforced with 0.5 to 1.0 wt% strontium (Sr) by casting technique. Then, the Al-Mg-Sr composite alloy was characterised by its mechanical properties and microstructure characterization. An Instron tensile machine and a Vickers hardness tester were used to determine the tensile strength and hardness of the Al-Mg-Sr composite alloy. The Gamry potentiometer electrode was used to determine the corrosion rate of this composite alloy. From the results, increased Sr content increases the tensile strength and hardness of the Al-Mg alloy. Field emission scanning electron microscope (FESEM) results show that the synthesised composite alloys have a uniform distribution of reinforcement, which tends to be fine and associated with a clean interface with the metal matrix. X-ray diffraction (XRD) analysis confirms that only the elements Al, Mg, and Sr were detected during characterization. The morphology shows that the particles of the Sr phase have a dendritic structure. In the corrosion test with the Gamry potentiometer electrode, Al-Mg with a composition of 1.0 wt% Sr showed the best results in terms of corrosion rate compared to cast Al-Mg with 0.5 wt% and the Al-Mg alloy itself. All the summarised results show that Al-Mg alloy composites containing different weights of Sr phase were successfully fabricated and the particles were uniformly distributed in the matrix of the composites.

Formation of Deformation Bands during Impact Indentation of an Al–6Mg Alloy

The nucleation and growth of macrolocalized deformation bands initiated by impact indentation in deformed aluminum-magnesium alloy samples have been investigated by acoustic emission and highspeed video recording with a time resolution to 50 μs. The indenter impact has been found to trigger the developmentof a ~1–3% amplitude plastic deformation macroscopic jump due to the nucleation and propagation of about ten deformation bands on an alloy surface, thus demonstrating the Portevin–Le Chatelier effect. Macrolocalized deformation bands are shown to be a dangerous type of erosion damage that can cause thesudden fracture of an alloy.

Comparative analysis of the explosion characteristics of magnesium dust and magnesium-aluminium alloy dust with two concentrations

ABSTRACT Magnesium (Mg) dust and magnesium–aluminum (Mg–Al) alloy dust are commonly produced and form a dust cloud in industrial manufacturing processes, which considerably increases explosion risk. This study examined three metal dusts: Mg, 48 mass% Mg–Al alloy, and 91 mass% Mg–Al alloy. A 20-L spherical explosion device was used to investigate the effect of different Mg concentrations. The results revealed that for all the samples, the explosion pressure (P ex) first increased and then decreased for a dust cloud concentration of 100–1000 g/m3. With the increase of dust particle size, the P ex of samples decreased. With the increase of ignition delay time, the P ex of samples first increased and then decreased, reaching the peak at 60 ms. Under identical conditions, when Mg concentration increased, the alloys became less stable. Thermogravimetry-differential scanning calorimetry findings revealed that the oxidation process of samples could be divided into three stages. The initial oxidation temperature of the alloys was lower than that of the pure Mg; however, in its primary oxidation stage, the mass gain rate of the Mg dust was more rapid than that of the Mg–Al alloys. In the oxidation of the alloys, elemental Mg reacted with oxygen first.

Deformation characteristics and dislocation quantification of aluminum-magnesium alloy with different 〈0 0 1〉 tilt grain boundaries using MD simulation

Deformation characteristics and dislocation quantification of aluminum-magnesium alloy with different 〈0 0 1〉 tilt grain boundaries using MD simulation

The influence of some factors on the characteristics of metallized incendiary mixtures

In this article, the influence of some factors on the characteristics of metallized incendiary mixtures (pyrogels) was studied. The pyrogel-type contains benzene, polyisobutylene, magnesium, aluminum-magnesium alloy, sodium nitrate, and different additives. It is shown that the molecular weight of polyisobutylene, the amount of aluminum-magnesium alloy, the particle size of metal combustibles, and the amount and type of polyester threads have different effects on the heat of combustion, flash point, burning rate, flame height, and adhesion to the material surface. The optimal pyrogel contains 38-40% thickened benzene - PIB with molecular weight 175000-225000, 25-27% aluminum-magnesium alloy with particle size ≤ 160µm, 10-12% magnesium powder with particle size ≤ 180µm, 15% sodium nitrate, 8% phenol-formaldehyde resin and 1.5% (over 100%) 3D polyester threads.

Differences in Properties between Hybrid Wire Arc Additive-Milling Subtractive Manufactured Aluminum and Magnesium Alloys

Hybrid wire arc additive-milling subtractive manufacturing (HWMM) is an effective way to improve the quality of complex metal components, but the difference in the properties of the aluminum alloy and magnesium alloy fabricated by HWMM has been not addressed. In the paper, the differences in deposition accuracy and tensile anisotropy between the Al5Si Al and AZ31B Mg alloys were studied by using the HWMM method. Under the optimal parameters, the minimum surface roughness of the AZ31B sample was 146.1 μm, which was 90% higher than for the Al5Si sample. The differences in the tensile strength and elongation of the AZ31B sample were 32% and 56%, respectively, being 6 and 3.3 times higher than those of the Al5Si samples. According to the fracture behavior of the samples, the tensile anisotropy of both alloys was mainly attributed to defects such as incomplete fusion and porosity in the fusion line. However, there was obvious structural inhomogeneity in AZ31B samples, where the grain size difference between adjacent areas reached 40%. This led to the easier fracture of AZ31B samples. These results contribute to our understanding of the HWMM of light alloys.

AUSTRAL WRIGHT 5251

Abstract Austral Wright 5251 is a wrought, non-heat-treatable, aluminum-magnesium-manganese alloy (5xxx series). It is about mid-way in the series of aluminum-magnesium alloys for alloying content and strength, which is very similar to that of alloy 5052. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-494. Producer or source: Austral Wright Metals.

Dynamic hardness and formation of Portevin-Le Chatelier bands during impact indentation

The effect of shock indentation on the formation and propagation of the Portevin-Le Chatelier deformation bands in an aluminum-magnesium alloy was studied experimentally using acoustic emission and high-speed video recording methods. Dynamic and nonlinear responses to shock indentation are revealed: the first include high values of dynamic hardness and local strain and loading rates, and the second - threshold and multiple nature of force and acoustic responses. It is shown that the bands of macrolocalized deformation represent a latent bulk type of erosion damage, which reduces the mechanical stability and durability of the alloy. Keywords: contact shock, Portevin-Le Chatelier effect, deformation bands, fracture, aluminum-magnesium alloy.

In situ investigation of the mechanism of propagation of Portevin-Le Chatelier deformation bands

Based on the analysis of high-speed video data of propagating deformation bands in an aluminum-magnesium alloy, it was found that the movable deformation band contains an excess of dislocations of one mechanical sign, and the main mechanism for the propagation of the localized plastic deformation front along the sample axis is a relay transmission of sliding in the antiparallel direction to relax the bending moment created by the primary deformation band. It is shown that the "instantaneous" rate of plastic deformation during ~1 ms in the growing band reaches a value of ~103 s-1, comparable to the rate of deformation during shock tests. Keywords: intermittent deformation, vocalization, dislocations, mechanical charge, aluminum-magnesium alloy.

Influence of process parameters on machining studies on stir casted MMCs with AA6351 and TiO2 by grey and desirability approaches

In this paper stir casting technique is an efficient method to improve the mechanical characteristics. It was done only on the aluminium magnesium alloy with their ceramic reinforced materials. Therefore, Al 6351 is a base matrix and ceramic strengthening reinforcement particles Titanium oxide (TiO2) makes the metal matrix composites. It was mainly related with aerospace, automotive and ship industries applications. The TiO2 was increasing the weight fraction 4, 8 and 12 % with Al6351. After processing, the processed MMCs specimens was utilized to investigating the machining studies form their appropriate process parameters like speed, feed and depth of cut. The machining performances are related with surface roughness (SR) and Material removal rate (MRR). In this research, two multi-objective techniques grey relational analysis and desirability approaches was involved to identify the optimal machining parameters. From the outcomes, both output responses are improved with their process parameters. There is major reason behind that the increasing of TiO2 enhances the material properties.

Динамическая твердость и образование полос Портевена-Ле Шателье при ударном индентировании

The effect of shock indentation on the formation and propagation of the Portevin-Le Chatelier deformation bands in an aluminum-magnesium alloy was studied experimentally using acoustic emission and high-speed video recording methods. Dynamic and nonlinear responses to shock indentation are revealed: the first include high values of dynamic hardness and local strain and loading rates, and the second - threshold and multiple nature of force and acoustic responses. It is shown that the bands of macrolocalized deformation represent a latent volumetric type of erosion damage, which reduces the mechanical stability and durability of the alloy.

Investigation of lightweight wheel design using alloy materials through structural analysis

Researchers are focusing more on lightweight vehicle design in response to the automotive industry's growing emphasis on energy efficiency and ecological responsibility. Two important considerations, including safety and technical requirements, must be taken into account while constructing a wheel. The rim and spokes make up the construction of the wheel. The creation of cutting-edge wheel and spoke designs for an automobiles is the objective of this paper. The wheel has been subjected to a finite element analysis using ANSYS. Each material's stress and strain performances may be determined by taking into account magnesium alloy, aluminum alloy, and titanium alloy. When analysing the two different designs and three different materials, the findings of the equivalent stress and deformation were compared. This study makes some insightful predictions about the dependability of the structural design, and it offers some helpful references for the design and development of alloy wheels.

Microstructure, interfacial characteristics and wear properties of AZ31 surface selective laser cladding AlSi10Mg coatings

Aluminum-magnesium alloy dissimilar materials connected to make a composite structure, which can effectively make up for the shortcomings of magnesium alloy itself such as low hardness, and poor resistance to wear. The AlSi10Mg coating was successfully prepared on the surface of the AZ31 substrate by adding a transition zone using selective laser melting, which provides a new method for the composite of Mg-Al heterogeneous materials. The transition zone defects, coating microstructure, interfacial properties, and wear properties were studied. The results show that the formation of defects was mainly related to the unfused powder and oxide, and the transition layer thickness increases defects show a non-uniform increasing trend. Group A2 does not show defects and was the best parameter. It was well bonded with the substrate, and the hardness as a whole maintains a stable and high hardness value. Compared with the substrate, the wear resistance of the coating was improved, and its wear mechanism was mainly three-body wear, and the Si particles on the surface of the coating reduce the contact area of the friction pairs during sliding, which effectively improves the wear performance of the coating.