A356 Aluminum Alloy Research Articles

Mechanisms related to the influence of natural aging on the precipitation behavior of the A357 aluminum alloy during artificial aging

This study investigated the influence of natural aging (NA) on the precipitation behavior of the main precipitate β″ and hardness evolution during the subsequent artificial aging (AA) process of the precipitation strengthened A357 aluminum alloy. The corresponding mechanisms were analyzed. The results demonstrate that natural aging has adverse influence on the precipitation process during artificial aging. The underlying mechanism is that small GP zones are formed during natural aging but cannot become nucleation sites for the β″ phase during artificial aging, which spontaneously consumes the supersaturated solute atoms in the Al matrix, increases the nucleation barrier of the β″ phase, and also consumes the vacancies produced after solid solution and quenching, thereby reducing the nucleation rate of the β″ phase during artificial aging, and leading to an un-expected increase in the size of the precipitated phase, thus reducing the peak aging hardness of the alloy. This effect becomes more pronounced with increasing natural aging time. Increasing the artificial aging temperature can improve the nucleation rate of the β″ phase during artificial aging, thereby to some extent reducing the unfavorable influence of natural aging on the artificial aging by reducing the sizes and increasing the amount of the β″ precipitates.

Analysis of the Effect of Simultaneous Melt Shearing and Cooling on Grain Formation and Rheology of A356 Aluminum Alloy

Despite the dozens of earlier research verifications, the contribution of shearing of molten metallic alloys during their solidification to grain formation is still ambiguous. Also, modeling of this phenomenon has received very little attention. Experiments were conducted in this study to investigate the effect of the shear rate on the density, size, and shape factor of the formed grains up to a solid fraction of 0.15 for the solidifying A356 aluminum alloy in the coaxial cylinder viscometer. The rheology of the formed semisolid slurry was studied as well. Results exhibited morphological evolution and grain refinement. The grain number density increased from 5 × 108 m−3 in the absence of melt shearing to reach 4 × 109 m−3 at the shear rate of 250 s−1. Also, the shape factor was improved to reach 0.78. Based on the experimental investigations, the grain number density under shearing was correlated to the shear rate and the grain number density in the absence of shearing via an empirical formula. A shear-dependent grain multiplication factor was deduced. The alloy exhibited a shear-thinning behavior where the viscosity obeyed the power law with a constant and an exponent of 0.9264 and 0.468, respectively. Moreover, the measured data were fitted to several proposed viscosity models and the model of Hirai et al. showed the best fit; therefore, it was recommended for predicting the viscosity of semisolid slurries.

Effect of static elastic stress on the corrosion behavior of 7A04 aluminum alloy exposed to real marine atmospheric environment

Aluminum alloy structural materials are widely subjected to the interactive effect of atmospheric corrosion under thin liquid film and elastic stress during the actual service. This study utilized the real marine atmospheric environment as the corrosion environment of thin liquid film for 7A04 aluminum alloy, and the specially designed outdoor device was used to apply varying levels of static elastic tensile stress at the same time, and then the corrosion damage behavior of 7A04 alloy under the interactive effect was studied. The research indicates that the 7A04 alloy suffers from pitting and exfoliation corrosion under the test conditions. The applied elastic tensile stress can accelerate the corrosion damage process of 7A04 alloy, and the degree of acceleration increases with increasing stress levels and exposure time. Moreover, the applied stress can also significantly accelerate the deterioration of the mechanical properties of 7A04 alloy, which has a more prominent effect on the elongation after fracture. Additionally, the corrosion mechanism of 7A04 alloy under the interactive effect was also discussed in this paper.

Research on hole inhibiting mechanism of 5A06 aluminum alloy during laser oscillating fuse deposition forming

Research on hole inhibiting mechanism of 5A06 aluminum alloy during laser oscillating fuse deposition forming

Study on filiform corrosion of A356 aluminum alloy under an organic coating

Due to its excellent performance, aluminum alloys are frequently used in wheels, but the corrosion of aluminum alloy wheels is still a major problem to be further studied. To understand the corrosion of wheels, it is important to consider the role of the organic coating in the corrosion process. Meanwhile, it is also meaningful to find an effective method to remove the organic coating properly to investigate the corrosion products under the organic coating. In this paper, the corrosion status of the A356 aluminum alloy substrate under an organic coating was observed firstly; lipid solutions such as NMP solution and butyl acrylate solution were used to remove the coating, and comparative experiments were carried out by controlling factors such as the soaking temperature, time, composition of solution etc. To find out the optimized soaking method to remove the organic coating; finally, the morphology of the localized corrosion on the aluminum alloy surface and the composition and structure of the corrosion products on the aluminum alloy substrate were analyzed. Results show that the corrosion products mainly contain ZrO2, Zr3O2F8, AlO(OH), and Al2O3. The corrosion process prefers to initiate at the defects where the coating and the substrate are not tightly bonded. This work shows the corrosion behavior of the aluminum alloy under an organic coating and provides a useful method to remove the organic coating from the aluminum alloy substrate effectively, and the results can be valuable for the understanding and mitigation of metal corrosion under an organic coating.

Wear Resistance of Aluminum Alloy A356 After Thorough Anodic Oxidation

Wear Resistance of Aluminum Alloy A356 After Thorough Anodic Oxidation

Abrasive Wear Properties Evaluation of the Thixoformed A380/NbC Composite

Composite materials are increasingly being used in several areas, especially in the automotive and aerospace industries, however, during regular operation their wear is one of the main causes of failure. Consequently, developing and researching new composite materials is essential to increase and improve service life. In addition, thixoforming is claimed to exhibit superior properties by reducing typical defects in casting like shrinkage and porosity. Therefore, the main objective of this study is to produce and analyze abrasion wear properties of the thixoformed aluminum matrix composite reinforced with NbC, obtained by the stir-casting method. Three different composites with 5 wt.%, 10 wt.%, and 15 wt.% of NbC were manufactured with the stir-casting method, compared with A380 alloy. The procedure involves an A380 aluminum alloy that was molten at 750 °C. In sequence, niobium carbide powder was added by mechanical stirring for 10 min; Mg was added to improve the wettability between the reinforcement and matrix. Chemical grain refinement by Al-5Ti-1B master alloy was used for non-dendritic feedstock production. Hence, the induction furnace was used for the thixoforming process, to achieve a mushy of 60 % solid fraction at 562 °C, determined by Differential Scanning Calorimetry (DSC) analysis. The holding time applied was 90s. Optical microscopy (OM) and scanning electron microscope (SEM) analyses allowed the microstructural characterization. Abrasive wear tests, according to the ASTM G65 standard, showed an improvement of the composites’ abrasion wear resistance after the thixoforming process, with a higher amount of NbC, potentially increasing the range of use of this technology and materials.

Self-healing metal matrix composite of nitinol wire-reinforced A356 alloy matrix by stir casting technology

The current demand for novel and self-healing material in today’s industries is one of the key challenges. Many engineering applications required tailored properties including self-healing characteristics in novel engineering materials. In this regard, an attempt is made to develop the metal matrix composite of aluminum A356 alloy by utilizing the properties of Nitinol alloy (wire) through a semi-solid metal processing technique. The investigation was validated by light-microscope images of the developed material. Further, filed emission scanning electron microscopy images are taken from the specimens for morphological examination. The elemental confirmation of the produced material is conducted through Energy Dispersive X-Ray Analysis (EDX) spectrum. The results revealed the random dispersion of reinforcement in the matrix phase and EDX confirms that the major constituents of A356 alloy and the Nitinol wires. At last, the crack analysis is conducted before and after hearing which reveals that the interlocks of Nitinol wire with the alpha Al phase of base alloy can provide the ability to close the crack and it can recover the deformed surface by 17.35%.

Effect of simple repair using resin on fatigue life of A6063 aluminum alloy with a simulated crack

Effect of simple repair using resin on fatigue life of A6063 aluminum alloy with a simulated crack

Influence of Compound Laser on Paint Removal Depth and Performance of 6005A Aluminum Alloy

Influence of Compound Laser on Paint Removal Depth and Performance of 6005A Aluminum Alloy

Mechanical properties of refractory HEA WNbTaV and its penetration behavior to aluminum alloy plate

Quasi-static and dynamic compression experiments were conducted on WNbTaV to investigate its mechanical characteristics and its penetration behavior into an aluminum alloy target plate. Additionally, ballistic experiments with WNbTaV projectiles against 2A12 aluminum alloy thin targets were performed. The results indicate that HEA WNbTaV at a strain rate of 10−3 s−1 has a fracture strength of 1340 MPa, a yield strength of around 980 MPa, and a fracture strain of less than 7%. However, its dynamic yield strength is almost twice its quasi-static yield strength, and its dynamic fracture strain is more than twice the quasi-static compression fracture strain.When striking a 2 mm thick 2A12 aluminum alloy target plate with a velocity less than 348.5 m/s, the HEA WNbTaV projectile remains stiff and undeformed. Its maximum velocity before entering the target plate is roughly 273 m/s. Furthermore, within a certain impact velocity range, the residual velocity, initial impact velocity, and ultimate penetration velocity of the HEA WNbTaV projectile penetrating the 2 mm thick 2A12 aluminum alloy target plate meet the following relationships. vr=v02−2.13vb2.

Operating effect of filler on filling roll bending of integral panel

A filling roll bending process of a 2A12 aluminum alloy integral panel with polypropylene as filler was studied. The operating effect of filler was revealed, based on analytical, numerical, and experimental methods. The results show that the position difference of the neutral layer between the ribs and the web of the integral panel leads to the error of generatrix straightness, and the filler can reduce this difference. A certain range of the width gap (1–3 mm) between filler and rib can avoid the instability of the rib and the curl of the filler. The height gap between filler and rib determines the compression degree of filler. The best pressure transmission effect can be achieved as the filler is still higher than the rib (1 mm) after compression. The elastic modulus of filler slightly affects the forming accuracy of the integral panel within a certain range (450–1300 MPa). Still, the filler transfers insufficient pressure under lower elastic modulus (50 MPa) and limits the deformation of the integral panel under higher elastic modulus (20 GPa). Experimentally measured generatrix straightness verified the operating effect of filler.

Simulation and Optimization of the Auxiliary Cathode for Inter-Electrode Discharge Electric Field in Microarc Oxidation.

Currently, research on the edge effect issue in the micro-arc oxidation process primarily focuses on investigating process conditions and enhancing additives. However, some scholars have utilized finite element analysis software to simulate the edge effect during the simulation process, overlooking the investigation of the morphology of the auxiliary cathode. This study analyzes the growth characteristics of the oxide film on aluminum alloy 2A12 during micro-arc oxidation. Additionally, the inter-electrode discharge electric field is simulated using the finite element analysis method. The auxiliary cathode is optimized to mitigate the influence of the edge effect on the film layer. The findings indicate that employing a cylindrical shape as the auxiliary cathode instead of a rectangular groove leads to an increased thickness of the micro-arc oxidation film. However, it also results in an augmented length of the film layer affected by the edge effect at both ends of the workpiece. Decreasing the distance between the auxiliary cathode and the workpiece surface leads to a higher thickness of the obtained micro-arc oxidation film. Decreasing the length of the auxiliary cathode results in a reduction in both the thickness of the film layer on the workpiece surface and the area affected by the edge effect. Increasing the eccentric cone ratio of the auxiliary cathode enhances the uniformity of the micro-arc oxidation film layer. In this study, we present a novel auxiliary cathode model that incorporates a smaller cylindrical shell at the center and eccentric cone shells on each side. This model has the potential to enhance the optimization rate of the micro-arc oxidation film layer on cylindrical workpieces by 17.77%.

Analysis and optimization of the stamping process with pretreated 7A09 aluminum alloy

Analysis and optimization of the stamping process with pretreated 7A09 aluminum alloy

A modified Johnson–Cook model for 2A12 aluminum alloys

A modified Johnson–Cook model for 2A12 aluminum alloys

Entrainment defects in semi-solid A356 aluminum alloy treated by ICTE process

The entrainment defects generated during the preparation of semi-solid slurries following the rheocasting technique impart poor mechanical and comprehensive properties to the casting. However, the mechanism of formation of these defects in semi-solid slurry has rarely been studied, so the mechanism of the formation of entrainment defects in the semi-solid A356 aluminum alloy be herein reported. The speed of the thermal equilibrium body (TEB) was maintained at 1300 and 2500 rpm where the entrainment defects of slurry were analyzed under conditions of internal cooling thermal equilibrium (ICTE). Results obtained using the SEM and computed tomography revealed the formation of bifilm defects, bubble trails, gas pores, and shrinkage pores in the slurry produced when the speed of rotation was 2500 rpm which resulted in lower elongation. The tensile specimens fabricated at the 2500 rpm speed were worse than those fabricated when the rotational speed was 1300 rpm in the aspect of elongation and reliability of mechanical properties. Results from numerical simulation and water simulation indicated that the phenomenon of surface turbulence promoted the formation of entrainment defects, and the bubbles entrapped inside the slurries could not escape according to the bubble theory floating calculation.

Study on the Effect of Microstructures and Properties of Al-Mg-Mn-Zr Alloy Welding Wire by Adding Minor Sc

The low strength of welded joints of aluminum alloy welding wire materials has seriously restricted the promotion and application of high-performance aluminum alloys represented by 7A52 and 7B52 aluminum alloy. It is urgent to develop new high-strength aluminum alloy welding wire material to meet the lightweight application demand of 7××× series high-performance aluminum alloy materials in military and civilian vehicles. This paper studied the effect on microstructures, mechanical properties, and welding properties of Al-6Mg-0.3Mn-0.2Zr welding wire alloys by adding minor Sc elements. The result shows that it formed Al3Zr, Al3Sc, and Al3(Sc1-x, Zrx) primary dispersive phases in the matrix, and the Al3(Sc1-x, Zrx) primary phase, which had triple-shell microstructure composed of Al3Zr/α(Al)/Al3Sc three-layer phases enclosing individually with each other from the center to outside. These phases could promote heterogeneous nucleation during solidification and crystallization in the process of welding, resulting in strong refinement and strengthening effects in the weld-zone microstructure. The welding joint mechanical properties of both tensile strength and elongation increased with the increase of Sc contents within the range of 0–0.4%. It was reached at Rm 365 MPa/A 5% without means of heat treatment which are much higher than aluminum alloy welding wires used in current engineering when the 7B52 aluminum alloy laminated plates were welded with the prepared welding wire Al-6Mg-0.3Mn-0.2Zr alloys of 0.385% Sc.

Modeling of Yield Surfaces for A5052 Aluminum Alloy Sheets with Different Tempers by Simplified Identification Method and Its Experimental Validation

Modeling of Yield Surfaces for A5052 Aluminum Alloy Sheets with Different Tempers by Simplified Identification Method and Its Experimental Validation

Combined experimental-numerical analysis of A356 aluminum alloy friction surfacing on AA2024 aluminum alloy substrate

This study examined the influence of the rotational speed of an A356 aluminum alloy consumable rod on thermo-mechanical issues, microstructure, and the wear resistance of coating during friction surfacing on an AA2024 aluminum alloy. The study utilized a comprehensive experimental-numerical analysis to fulfill its objectives. The findings reveal that the width and thickness of the coating increase by 7 and 18% percent, respectively, as the rotational speed of the consumable rod is augmented from 600 to 800 revolutions per minute (rpm). A higher rotational speed of the consumable rod facilitates plastic deformation of the material within it, enabling softer material to be deposited on the substrate's surface under reduced axial force. Simulation outcomes display that the maximum plastic strain is experienced on the coating's upper surface, which contacts the tip of the consumable rod. Upon moving toward the interface between the coating and the substrate, the degree of plastic strain rapidly diminishes. In the coatings produced by rotational speeds of 600 and 800 rpm, a fine grain layer forms on the upper side of the coating that comes into contact with the consumable rod's tip. Friction surfacing utilizing a rotational speed of 800 rpm, a traverse speed of 125 mm/min, and an axial feeding rate of 100 mm/min, results in increases of 9 and 38% in hardness and wear resistance respectively, compared to the AA2024 substrate.

A new constitutive model and hot processing map of 5A06 aluminum alloy based on high-temperature rheological behavior and higher-order gradients

To develop a high-precision constitutive model and hot processing map for 5A06 aluminum alloy, the hot deformation behavior of the alloy was investigated through isothermal compression experiments and microstructure analysis experiments, which were conducted at temperatures ranging from 573 K to 773 K and at strain rates ranging from 0.01 to 10 s−1. Firstly, a new constitutive model, which is based on the partial derivatives of the experimental flow data and does not significantly increase the material parameters, was proposed. Secondly, a comparison and analysis of the predictive accuracies of both the new model and the classic model were conducted. Finally, the new constitutive model was used to construct the hot processing maps of the 5A06 aluminum alloy, and the optimal hot processing parameters were validated through metallographic experiments. The results show that a high-precision constitutive model can be constructed with a small number of material parameters by considering the second-order approximation between logarithmic stress and temperature, as well as the third-order approximation between logarithmic stress and logarithmic strain rate. The mean square errors of the new model were significantly lower than those of the Arrhenius model and Hense-Spittle model for all strain rates and temperatures. There were significant differences in the prediction accuracy of the AH and HS models at different temperatures and strain rates, indicating their accuracy was dependent on temperature and strain rate. The coefficients of the new model were significantly higher than those of the AH and HS models. Moreover, the proximity of predicted values to experimental values was ranked in descending order as follows: new model, AH model, and HS model. The energy dissipation rate is relatively high when the strain rate is lower than 10 s-1 and the temperature is higher than 623 K. The instability factor is larger than zero for all conditions except when the strain rate is equal to 10 s−1. The optimal hot working temperature range for 5A06 aluminum alloy is 623–700 K, and the strain rate should be in the range of 0.01 s−1 to 1 s−1. The microstructure analysis matches the predicted results from hot processing maps, which can guide the hot working process of 5A06 aluminum alloy.