Types Of Aluminum Alloys Research Articles

Study of forming limit diagram (FLD) prediction of anisotropic sheet metals using Gurson model in M-K method

This study uses the Marciniak and Kuczynski (M-K) method to present an analytical forming limit diagram (FLD) for sheet metals. The procedure for the analytical FLD prediction is described in detail and step-wise manner, and an algorithm is written using MATLAB. First, an appropriate algorithm is determined to establish the theoretical analyses, and various anisotropic yield functions, such as Hill’s 48, Barlat 89, and Hosford, are considered. The predicted FLDs are compared with experiments involving a typical AA6016-T4 aluminum alloy. Second, the Gurson model that considers damage growth is implemented when Hosford is the yield function, as Hosford criterion predicts the best comparable analytical FLD with experiments among the yield functions. Third, a parametric study is performed to investigate the effects of parameters on the FLD prediction. Results indicate that an extremely low value for the initial void volume fraction in the safe and groove zones has minimal effects on the FLD prediction. Lastly, the values of void volume fractions are calculated assuming no geometrical imperfections and the imperfection is because of higher void volume fraction in groove zone than that in safe zone.

Effect of tool axis offset and relative position of materials on the performance of dissimilar friction stir welded aluminium alloy joints–an overview

At present most of the manufacturing sectors are looking for high strength lightweight structures with high specific stiffness and good corrosion resistance. In this context, combined use of different types of aluminium alloys are required and warrants efficient joining of the dissimilar alloys. But, efficient joining of dissimilar aluminium alloys by fusion welding techniques is very difficult due to the poor weldability of dissimilar aluminium alloys. It is reported that FSW being a solid state welding technique can avoid all problems associated with fusion welding and is a potential candidate technique for joining difficult to weld materials including dissimilar aluminium alloys. With regard to FSW dissimilar aluminium alloys, the tool axis offset and relative positioning of alloys are also reported to be important. In this article, a comprehensive discussion on the influence of tool axis offset and relative positioning of the materials on the joint performance that reported in the literature is presented. The literature showed that there is uniqueness in the value and sign of the tool axis offset that can result defect free joint with good joint properties. With regard to relative positioning of the materials also, conflicting arguments are reported in the literature.

Optimized preparation of deep cryogenic treated steel and Al-alloy samples for optimal microstructure imaging results

The research investigates the varying effect of commonly used etchants for revealing the microstructure of steels and aluminum alloys. Selected representatives of different types of tool steels and aluminum alloys were chosen to indicate the general effects of etching on different phases with different elemental contents and enrichments. The representatives were also investigated under two different preparation states. One state of the materials was selected based on the heat and forming processing determined by the producer of the selected materials. Whereas the other state is developed by a modified heat treatment procedure with included deep cryogenic treatment processing step. The purpose of this study is to provide a systematic overview for the evaluation of microstructure of selected materials with various etching reagents based on their different processing history. The intent of this research is also to deliver clear guidelines to the growing community involved in cryogenic processing of metals for the most in-depth microstructural observation with etching of the metallographically prepared sample surface. It was determined, that the optimal etching reagents are different for the same materials under different processing conditions. For the cryogenically treated tool steels, the optimal reagents for both examples was determined to be nital and Groessbeck’s reagent. Whereas for the aluminum alloy the combination of Weck’s and modified Keller’s reagent was determined as the most optimal etching reagents.

Formation of Phases and Microstructures in Al-8Si Alloys with Different Mg Content.

Mg-containing high-silicon aluminum alloy is a heat-treatable aluminum alloy that is now widely used in the aerospace and automotive industries because of its high specific strength, high wear resistance and corrosion resistance, low thermal expansion coefficient, and low cost. More attention has been paid to optimizing the microstructure to increase the performance of this type of aluminum alloy. In the present work, the solidification processes of Mg-free and Mg-containing (0.33–1.32%) Al-8Si alloys were analyzed by the experimental results combined with the thermodynamic calculation. The results showed that α-Al, Si, and Al5FeSi were in the Mg-free Al-8Si alloy ingots, while the Al5FeSi phases in alloys with Mg additions were transformed into π phases (Al8Mg3FeSi6) by the reaction L+Al5FeSi→α-Al+Si+Al8Mg3FeSi6. There was a binary eutectic reaction of L→α-Al+Al5FeSi when the Mg content exceeded 0.51% and the Fe content was higher than 0.17%. With the increase of Mg content, the volume of Mg2Si was gradually increased while the divorced eutectic phenomenon of the quaternary eutectic structure (α-Al+Si+Mg2Si+Al8Mg3FeSi6) was weakened and the eutectic structure was significantly refined.

Identification of aluminum alloy by laser‐induced breakdown spectroscopy combined with machine algorithm

AbstractDiscarded aluminum alloys are a form of recyclable metal materials, and their classification and identification are highly important. In this work, laser‐induced breakdown spectroscopy (LIBS) technique combined with principal component analysis (PCA) and least‐squares support‐vector machine (LSSVM) algorithm were used to classify and identify five types of aluminum alloys. Exploratory analysis of five types of aluminum alloys by PCA was performed to achieve better segregation. The identification accuracy of the support‐vector machine (SVM) and LSSVM for aluminum alloy were 98.33% and 100%, respectively. The higher identification success rate was obtained using the LSSVM algorithm. Therefore, the LIBS technique combined with the PCA and LSSVM algorithms represents an efficient approach to identifying aluminum alloys.

Evaluation of bonding integrity of hybrid-built AlSi10Mg-aluminium alloys parts using the powder bed fusion process

Recent advances in metal additive manufacturing (AM) technology enable complex conformal cooling channels to be fabricated for injection and blow mould inserts. However, high manufacturing costs hinder the technology being adopted in the mould-making industry. A cost-effective hybrid strategy was developed for the powder bed fusion (PBF) process in which powder materials get additively deposited onto pre-machined substrates as a practical cost-reduction solution. In this study, the interface bonding integrity, in terms of microstructure and mechanical properties, of powder AlSi10Mg and three types of substrate aluminium alloys were evaluated. Microstructure analysis revealed excellent powder-substrate fusion across the narrow interface of the three samples. All tensile specimens ruptured at least 5 mm away from the bonded interface, at the side where the material was of lower strength. Samples fabricated with AlSi10Mg-Alumec 89 alloys had the highest tensile strength of 481 MPa, about the same as standard as-built AlSi10Mg aluminium. Using the PBF-machined substrate hybrid AM strategy, Alumec 89, a high strength tooling-grade aluminium alloy, can be used as the base substrate for the fabrication of durable and high-performance aluminium injection and blow mould inserts.

Force and pressure function formulation for direct cold extrusion of aluminum alloy Al 1350 using regression method

Purpose. Establishing methodology in order to determine mathematically both extrusion force and pressure functions for Aluminum alloy AL 1350 using the regression method of experimental data. Methodology. Several variables (diameter of the cavity for pressing D, degree of extrusion, angle of the punch head cone 2, and ratio of the semi-finished sizes Rs) were included when using the regression method considered. Findings. Diameter and strain were found to play a significant role in predicting both extrusion force and pressure functions associated with the extrusion process. Mathematical formulas for force and pressure were obtained using the regression method. Amethodology has been developed for the mathematical determination of extrusion force and pressure. Originality. Force and pressure functions in direct cold extrusion process are mainly required for the design of extrusion dies. However, the existence of such data in the literature is insufficient to implement the process for direct cold extrusion of aluminum and aluminum alloys as well as for other materials. Results of the study consider the main factors influencing extrusion force and pressure as well as the main differences for types of aluminum alloys. Practical value. The mathematical formulas obtained by the regression method provide a mathematical tool for calculating force and pressure values in direct extrusion process.

Characterizing the Soldering Alloy Type Zn–Al–Cu and Study of Ultrasonic Soldering of Al7075/Cu Combination

The aim of the research was to characterize the soldering alloy type Zn–Al–Cu and study the fluxless ultrasonic soldering of the combination of aluminum alloy type Al7075 with copper substrate. The Zn–Al–Cu solder is of the close-to-eutectic type with two phase transformations: the eutectic transformation at 378 °C and the eutectoid transformation at 285 °C. The solder microstructure is formed of a matrix composed of the solid solutions of aluminum (Al) and zinc (Zn) in which the copper phases CuZn4 and CuAl2 are precipitated. The shear strength of the soldering alloy type Zn5Al with copper addition reaches values from 167 to 187 MPa and it depends on the copper content in the solder. The bond with aluminum alloy type Al7075 is formed due to the solubility of Al in zinc solder at the formation of solid solution Al. Contrary to this observation, the bond with the copper substrate is in this case formed due to the interaction of zinc and aluminum with the copper substrate. Two new intermetallic phases, namely Al(Cu,Zn)2 and Cu3.2Zn0.7Al4.2, were formed. The average shear strength of Al7075/Zn5Al3Cu/Cu joints attained was 134.5 MPa. For comparison, the Cu/Zn5Al3Cu/Cu joint attained an average shear strength of 136.5 MPa.

Research on Microstructure and Mechanical Properties of Rheological Die Forging Parts of Al-6.54Zn-2.40Cu-2.35Mg-0.10Zr(-Sc) Alloy.

High-strength aluminum alloy (mainly refers to the 7xxx series) is the optimum material for lightweight military equipment. However, this type of aluminum alloy is a wrought aluminum alloy. If it is directly formed by traditional casting methods, there will inevitably be problems such as coarseness, unevenness, looseness, and hot cracking in the structure, which will greatly affect the final performance of the part. Based on the internal cooling with annular electromagnetic stirring (IC-AEMS) method, a new technology of rheological die forging is developed in this paper, and the scale-reduced parts of a brake hub of Al-6.54Zn-2.40Cu-2.35Mg-0.10Zr aluminum alloy were prepared. The influence of IC-AEMS and the addition of rare element Sc on the structure and mechanical properties of the parts was studied. An optical microscope and scanning electron microscope (SEM) were used to observe the microstructure evolution, energy dispersive spectroscopy (EDS) was used to analyze the phase distribution and composition, and the mechanical properties of the parts were tested by uniaxial tensile tests. The results show that the addition of Sc element can effectively refine the grains and improve the strength and elongation of the material; the application of IC-AEMS improves the cooling rate of the melt, increases the effective nucleation rate, and the grains are further refined. Through process optimization, scale-reduced parts of a brake hub with good formability and mechanical properties can be obtained, the ultimate tensile strength is 597.2 ± 3.1 MPa, the yield strength is 517.8 ± 4.3 MPa, and the elongation is 13.7 ± 1.3%.

Numerical investigation and design of aluminium alloy channel section columns at elevated temperatures

Aluminium alloys are increasingly popular in structural engineering applications because they have high strength, low weight and great durability. However, the mechanical properties of aluminium alloy material may be significantly affected by high temperature. This paper presents a numerical study on the behaviour of aluminium alloy channel section columns at elevated temperatures. A non-linear finite element (FE) model was developed and validated against 27 experimental results at high temperature. The validated FE model was used to conduct an extensive parametric study, in which a total of 360 aluminium alloy channel section columns were generated at elevated temperatures. The key parameters for the parametric study include two types of aluminium alloys (6061-T6 and 6063-T5), three lengths (360 mm, 1000 mm and 2000 mm) of columns and ten temperatures (range from 24 °C to 600 °C). The design strengths were calculated using American, Australia/New Zealand and European Standards and compared with the numerical results generated from parametric study. In addition, a reliability analysis was used to assess the reliability level of the considered design methods.

The Effect of Pre-strain and Subsequent Electrically Assisted Annealing on the Mechanical Behaviors of Two Different Aluminum Alloys

The effects of pre-strain and subsequent electrically assisted annealing on the mechanical behaviors of two different (Al–Mg and Al–Si–Mg) aluminum alloys during electrically assisted dual stage forming are experimentally investigated. First, a specimen is deformed to a specific pre-strain by uniaxial tension and then automatically unloaded. After that, the pre-strained specimen is subjected to electrically assisted annealing by electric current with a fixed subsecond duration. Finally, the specimen is reloaded until fracture. Experimental results show that application of electric current with a subsecond duration induces electrically assisted annealing to both pre-strained aluminum alloys. The electric current also increases total achievable elongation until fracture during electrically assisted dual stage forming for both aluminum alloys. However, analysis of the stress–strain behavior during reloading and microstructural observations suggest that the quantitative effects of electric current on the post-electrically assisted annealing mechanical behavior and resultant microstructure are strongly dependent on the type of aluminum alloy. With the electric current density of 140 A/mm2, a full recrystallization followed by grain growth occurs in the pre-strained Al–Mg alloy specimens. For the pre-strained Al–Mg–Si alloy specimens, the electric current density of 140 A/mm2 induces both annealing and solid solutioning. Together, our findings indicate that while electrically assisted annealing is effective at improving the productivity of dual stage forming of an aluminum alloy, the composition of the aluminum alloy should be carefully considered in the design of forming process utilizing the concept of electrically assisted annealing since the beneficial effect was limited for the precipitation hardening 6061-T6 aluminum alloy.

Surface pre-treatment of aluminum alloys for the deposition of composite materials

Experiments reported in this paper issue on the behavior of two types of aluminum alloys (A2014 and A7075) before and after surface treatments. Each sample of alloys was cleaned and degreased in acetone by ultrasound, and the chemical roughening process involves two steps: etching in NaOH solution and desmutting in HNO3 solution, followed by washing with deionized water to remove the secondary reaction products.The microstructural characterization and morphological analysis of the alloys surface before and after treatment processes were investigated by OM, FE-SEM, EDX and FTIR. Also, the effect of solutions on surface roughness of aluminum alloys was determined by variation of weight and thickness according to the applied process, and the hydrophilic or hydrophobic character was measured by determining the contact angle. The obtained results highlight the need for the alloy surface processing steps in order to ensure adhesion and good compatibility with different types of composite materials.

Low pressure casting technology and forming process analysis of metal mold based on ProCAST FEA procedure

In order to simulate the casting process of a typical aluminum alloy, a 3 D entity model for a pouring system was used for numerical analysis of the filling and solidification process with ProCAST software. A comprehensive analysis including the change of temperature field, the velocity of filling, the solid phase as well as the location of casting defect, showed that the defects such as shrinkage (cavity) porosity can be reduced effectively with an increase in the mold preheating temperature and the number of vents. This simulation also serves as a theoretical reference for the sake of facilitating casting quality.

Significantly improved particle strengthening of Al–Sc alloy by high Sc composition design and rapid solidification

Sc alloying is usually carried out by adding a small amount of Sc in typical aluminum alloys to improve the mechanical properties, however, the effect of high-Sc content on the microstructure and properties of aluminum alloys is rarely concerned. To further understand the role of Sc alloying, several Al–Sc binary alloys with high-Sc content are designed and the relationship between the Sc content and mechanical properties were investigated. It is found that the mechanical properties of Al–Sc binary alloy is determined by both the Sc content and the cooling rate. The addition amount of Sc shows relatively small effect on the mechanical properties at low cooling rate, but higher at high cooling rate, because cooling rate turns the size and distribution of Al3Sc particles. Through the high Sc content alloy design and melt spinning rapid cooling technology, the densely distributed Al3Sc precipitate of about 250 nm can be located inside the α-Al grains, resulting in the intracsystalline reinforcement. The combination of high tensile strength (344 MPa) and good plasticity (5.7%) were achieved at a grain size of ~500 nm in the hypereutectic Al–Sc binary alloys ribbons. The significant strengthening could be attributed to multiple strengthening mechanisms including (1) Orowan strengthening; (2) coefficient of thermal expansion (CTE) mismatch strengthening; (3) the Hall-Petch effect caused by grain refinement; (4) solid solution strengthening. When the cooling rate is increased, the effects of thermal mismatch strengthening and Orowan mechanism are more prominent, significantly improving the strength of the Al–Sc alloy. The present experimental results provide an insight into the understanding of microstructural evolution of nanoparticles, and extend the effort for the development of hypereutectic Al–Sc alloys as a member of high-strength structural materials.

Dynamic penetration of cellular solids: Experimental investigation using Hopkinson bar and computed tomography

Light-weight cellular solids, such as aluminium foams, are promising materials for use in ballistic impact mitigation applications for their high specific deformation energy absorption capabilities. In this study, three different types of aluminium alloy based in-house fabricated cellular materials were subjected to dynamic penetration testing using an in-house experimental setup to evaluate their deformation and microstructural response. A two-sided direct impact Hopkinson bar apparatus instrumented with two high-speed cameras observing the impact area and the penetrated surface of the specimens was used. An advanced wave separation technique was employed to process the strain-gauge signals recorded during the penetration. The images captured by one of the cameras were processed using an in-house Digital Image Correlation method with sub-pixel precision, that enabled the validation of the wave separation results of the strain-gauge signals. The second camera was used to observe the penetration into the tested specimens for the correct interpretation of the measured signals with respect to the derived mechanical and the microstructural properties at the different impact velocities. A differential X-ray computed tomography of the selected specimens was performed, which allowed for an advanced pre- and post-impact volumetric analysis. The results of the performed experiments and elaborate analysis of the measured experimental data are shown in this study.

Comparison of the Resistance Spot Weldability of AA5754 and AA6022 Aluminum to Steels

In this paper, a traditional resistance spot welding (RSW) process in combination with a GM-patented Multi-Ring Domed (MRD) electrode was used to join two types of aluminum alloys, AA5754-O and AA6022-T4, to interstitial-free low carbon steel (LCS). Parallel studies were carried out for AA5754-LCS and AA6022-LCS resistance spot welds to investigate the effects of aluminum contact resistance on the weld profile, interfacial microstructure, defect distribution, and coach peel performance. The results indicated AA5754-O develops a higher contact resistance when ex-posed to atmospheric conditions. This resulted in a degradation of the RSW process due to increased internal expulsion of the molten aluminum nugget and concurrent reduction in aluminum nugget size that contributed to a loss in joint mechanical performance. By contrast, AA6022-T4 exhibited a lower contact resistance, which minimized internal expulsion and promoted the retention of larger aluminum nuggets. The larger AA6022 weld nuggets exhibited improved mechanical performance in comparison to the smaller 5754 nuggets.

G EFFECT OF VIBRATION-CORROSION ON ALUMINUM ALLOY(DIN1100) THAT WELDED BY TIG TECHNIQUE AND OPERATING IN THE MARINE ENVIRONMENT

In this research studied the effect of corrosion in presence of vibration on aluminum alloy type (DIN1100) operating in sea water (3.5% NaCl) and compared these results with the same alloy after it was welded by TIG technique at the same vibrated corrosive medium, addition to study the corrosion in static medium for welded and non- welded alloy, then comparison between the four cases depending on corrosion rates and microstructures it was noted that ;the greatest percentage of corrosion rate was 43% of welded alloy at vibration-corrosion and least percentage of corrosion rate was 8% of non-welded alloy at static corrosion.

Effect of Pre-welding Heat Treatment on the Mechanical Properties of Friction Stir Welded Al–4 wt.%Cu Alloys

This research investigates the welding of aluminum alloy Al–4wt.%Cu using friction stir welding (FSW). Besides the traditionally studied FSW process parameters (i.e., pin rotational and transverse speeds), this work addresses the effects of two pre-welding heat treatment conditions (annealing vs. age hardening) on the resulting weld joint. A set of experiments was carried out to assess joint quality under different levels of process parameters with specimens either annealed or age hardened prior to welding. The results revealed that age-hardened specimens prior to welding possessed higher hardness, higher penetration, and less wear rate among joint zones compared to the annealed ones and base metal. Moreover, the best joint quality was found to be obtained at higher welding and rotational speed regardless of pre-welding heat treatments. Findings of interest to industry, it is economically recommended to weld these types of high-strength aerospace aluminum alloys after age hardening.

Optimization of the Process Parameters in Milling of Aluminum Alloys

In order to control the temperature during milling process of aluminum alloys and keeping as minimum as possible, the choice of the cutting parameters and their optimization is very important, both for the tool wear but also for the surface quality of machined surface. The main purpose of this paper is to find the optimum values of the milling parameters (rotational speed and depth of cut) so that the minimum value for the temperature to be obtained. Using adequate experimental conditions with contact measurements techniques (thermocouple K-type) carried out on the some types of aluminum alloys and the appropriate statistical instruments, the most influencing cutting parameters and their values on the cutting temperature can be found. The results are presented both analytical and graphical.

Automatically weighted high-resolution mapping of multi-criteria decision analysis for sustainable manufacturing systems

A common feature of Multi-Criteria Decision Analysis (MCDA) to evaluate sustainable manufacturing is the participation (to various extents) of Decision Makers (DMs) or experts (e.g. to define the importance, or “weight”, of each criterion). This is an undesirable requirement that can be time consuming and complex, but it can also lead to disagreement between multiple DMs. Another drawback of typical MCDA methods is the limited scope of weight sensitivity analyses that are usually performed for one criterion at the time or on an arbitrary basis, struggling to show the “big picture” of the decision making space that can be complex in many real-world cases.This work removes all the mentioned shortcomings implementing automatic weighting through an ordinal combinatorial ranking of criteria objectively set by four pre-defined weight distributions. Such solution provides the DM not only with a fast, rational and systematic method, but also with a broader and more accurate insight into the decision making space considered. Additionally, the entropy of information in the criteria can be used to adjust the weights and emphasise the differences between potentially close alternatives.The proposed methodology is derived generalising a problem of material selection of automotive parts in metal casting manufacturing systems. In particular, three typical aluminium, magnesium and zinc alloys in a High-Pressure Die Casting (HPDC) process are compared using the deterministic Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) combining 18 criteria organised in 4 main categories (cost, quality, time and environmental sustainability). A detailed and systematic approach to calculate the considered criteria is also provided and it includes Life Cycle Assessment (LCA) considerations. Results show that, although in most of the cases the aluminium alloy is the best option, there are a few areas in the decision making space where magnesium and zinc alloys score better without a simple correlation to categories. This shows how valuable the proposed mapping process is to understand the complex MCDA analyses. The methodology does not make specific assumptions about metal casting and can be applied to sustainable manufacturing in general.