Mechanical Properties Of Aluminum Alloys Research Articles

Optimization of high-temperature mechanical properties of aluminum alloys through exclusive precipitation of T-phase

An aluminum alloy with an actual composition of Al - 5.4 wt%Cu- 1 wt%Mn was cast and subjected to solution heat treatment for 1 h, 2 h, 4 h, 8 h, and 16 h to make the T-phase the sole strengthening phase. The microstructural evolution of the samples, especially the T-phase microstructure, was studied using transmission electron microscope (TEM) and scanning electron microscope (SEM) with electron backscatter diffraction (EBSD) attachment. The ImageJ software was utilized to statistically analyze T-phase content. Tensile tests were conducted to obtain mechanical property data, and high-temperature tensile tests were performed at 200 °C, 300 °C, and 400 °C to assess the high-temperature performance. Subsequently, the strengthening effect of the T-phase on the room-temperature and high-temperature mechanical properties of the aluminum alloy was quantitatively evaluated. The sample subjected to an 8 h solution treatment exhibited optimal strength and toughness. The yield strength was 147 MPa, and the tensile strength was 300 MPa. The yield strength contributed by the T-phase was 73 MPa. The tensile strength of the sample at 400 °C remained at 91 MPa. The T-phase contributes significantly to the mechanical properties of the aluminum alloy both at room temperature and at high temperatures.

Investigations on Mechanical Properties of Nano Particulates (Al<sub>2</sub>O<sub>3</sub>/B<sub>4</sub>C) Reinforced in Aluminium 7075 Matrix Composite

Metal Matrix Nano Composites (MMNCs) with the addition of nano-particulate reinforcements can be of significance for automobile, aerospace, and numerous applications due to their low density and good mechanical properties, better corrosion and wear resistance, low coefficient of thermal expansion as compared to conventional materials. Designing the metal matrix composite material aims to combine the desirable attributes of metals and ceramics. The present work is focused on studying the mechanical properties of aluminium alloy (7075) with Al2O3 and B4C nanocomposite produced using the stir casting technique and ultrasonic cavitation method. Different % age of reinforcement is used. An ultrasonic cavitation technique is used to achieve a uniform dispersion of nano-particulate Al2O3 and B4C in molten aluminium alloy. Tensile, Hardness, and Impact tests were performed on the samples obtained by the fabrication processes. A structural study will be carried out through a Scanning Electron Microscope (SEM) to know the distribution of Al2O3/B4C Nano particulates in Al alloy.

Mapping the Mechanical Properties of Aluminum Alloys at Macro-to-Micro Scales

Mapping the Mechanical Properties of Aluminum Alloys at Macro-to-Micro Scales

CHARACTERIZATION OF SURFACE, SUBSURFACE DAMAGE AND THEIR EFFECT ON FATIGUE LIFE AFTER MACHINING OF AEROSPACE-GRADE ALUMINUM ALLOY (Al 6082-T6)

Aluminum alloys are widely used in the automotive and aerospace industries due to their lower mass-to-strength ratio than other metallic alloys. Apart from their inherent properties, aluminum alloys like other metallic alloys show a significant change in their mechanical properties according to the machining parameters. The research literature on obtaining optimum mechanical properties of aluminum alloys that undergo machining is very limited. Moreover, the combined effect of several parameters on the machinability of aluminum alloys has not yet been explored. In this paper, the effect of three machining parameters (Depth of Cut (DoC)), feed rate (FR), and cutting speed (CS) on the subsurface damage and fatigue life of aerospace-grade aluminum alloy (Al-6082-T6) is observed. Samples are prepared using a full fractional approach to effectively capture the effect of all input parameters. Thereafter, samples were subjected to surface roughness, micro-hardness, and fatigue life tests. Results of surface roughness and micro-hardness tests are compared with fatigue life. The general linear model was employed to capture the percentage effect of each input parameter on the output parameters. The results showed that DoC was the main contributing factor that caused subsurface damage, while surface roughness and fatigue life were mainly affected by FR and CS. Optical microscope images showed a white layer formation that had higher hardness than the base metal. Overall, this research work proposes the input parameters that can be used to achieve minimum surface damage and fatigue life.

Impact of Aging Time on the Metallurgical Properties and Hardness Characteristics of an Al-Si-Mg-Cr Hypoeutectic Alloy Intended for Automotive Applications

This research investigates the microstructural evolution and mechanical properties of LM25 (Al-Si-Mg) alloy and Cr-modified LM25-Cr (Al-Si-Mg-Cr) alloy. Microstructural analysis reveals distinctive ε-Si phase morphologies, with Cr addition refining dendritic structures and reducing secondary dendrite arm spacing in the as-cast condition. Cr modification results in smaller-sized grains and a modified ε-Si phase, enhancing nucleation sites and reducing ε-Si size. Microhardness studies demonstrate significant increases in hardness for both alloys after solutionising and aging treatments. Cr-enriched alloy exhibits superior hardness due to solid solution strengthening, and prolonged aging further influences ε-Si particle size and distribution. The concurrent rise in microhardness, attributed to refined dendritic structures and unique ε-Si morphology, underscores the crucial role of Cr modification in tailoring the mechanical properties of aluminium alloys for specific applications.

Estimation of Mechanical Properties of Aluminum Alloy Based on Indentation Curve and Projection Area of Contact Zone

This study proposes a method for determining aluminum alloys’ yield stress and hardening index based on indentation experiments and finite element simulations. Firstly, the dimensionless analysis of indentation variables was performed on three different aluminum alloys using the same maximum indentation depth to obtain load-displacement curves. Then, laser confocal microscopy was used to observe the residual indentation morphology. And four dimensionless parameters were derived from the load-displacement curves while another dimensionless parameter was obtained from the projection area of the contact zone. Subsequently, a genetic algorithm was employed to solve these five dimensionless parameters and estimate the yield stress and hardening index. Finally, the predicted results are compared with uniaxial tensile experiments and the results obtained are essentially the same. The yield stress and hardening index can be predicted using this method. And an example is used to verify that this method enables predictions for unidentified “mysterious material” and the expected results agree with the experiments.

Investigation of Modifying Alloying Elements in High-Pressure Injection Casting Eutectic Al-Si Alloys

In the study, the mechanical properties of aluminum alloys produced by the injection molding method, especially using Strontium and Titanium metals, were optimized without being subjected to cold forming. Mechanical tests were applied to the alloys produced by the high-pressure casting technique, and their strength, hardness, and microstructure were examined. Optical and SEM microscopy examinations investigated grain structures. Within the scope of the study, AlTi5B1 master alloy and AlSr10 master alloy were added to the pure AlSi10 (Fe) alloy in 5 different compositions. AlTi5B1 master alloy added to pure AlSi10(Fe) alloy significantly increased the hardness by reducing the grain size. Si modification took place with the addition of AlSr10 master alloy, and it was observed that the obtained weight ratios of 150ppm, 300ppm, and 450ppm Sr increased the hardness proportionally by 2.5 HB each. With the increase in Ti and Sr master alloys added, a significant increase was observed in tensile and yield strengths and % elongation rates. In the compression test, the percentage (%) deformation elongation, the reduction of the grain structure of the material by the added Ti and Sr elements, and the transformation of the eutectic silicon into a spherical structure absorbed the applied Fm force. This led to an increase in strength, and while the permanent deformation elongation decreased as the weight of Ti increased, it was observed that the permanent deformation elongation decreased proportionally with each added amount of 150 ppm Sr. The addition of the Ti element reduced the grain size by shrinking the α-Al dendrites, but it did not affect the eutectic Si.

Evolution of microstructure and mechanical properties of aluminum alloy induced by turning and ultrasonic surface rolling process

The microstructure and mechanical properties have a significant impact on the service performance of materials. This paper compared the microstructure and mechanical properties of 2024 aluminum alloy subjected to turning and ultrasonic surface rolling process (USRP). It was found that both turning and USRP can cause grain refinement and increased microhardness. The grain refinement induced by USRP was attributed to dislocation proliferation and T-phase fragmentation; At the same time, a quantitative relationship model between microhardness and microstructure during turning and USRP was constructed. The results showed that precipitation had the greatest impact on the microhardness induced by turning, while dislocations and grain refinement had the greatest impact on the microhardness induced by USRP; In addition, the mechanical performance response mechanism of the materials after turning and USRP was elucidated, and it was found that USRP can significantly enhance the yield strength of the materials.

Quenching optimization of a hot stamping line for aluminum automotive components

The rising cost of fuel and harder environmental regulations driving the need for more eco-friendly vehicles have compelled automotive manufacturers to search for innovative lightweight solutions. Consequently, hot stamped aluminum alloys are gaining prominence due to their exceptional specific strength and improved formability compared to cold formed components. Unfortunately, the current state of knowledge in the field lacks the necessary depth to establish a reliable, fast and optimized process for aluminum hot forming. To address this gap, a collaborative effort between Mondragon Unibertsitatea (knowledge provider), Fagor Arrasate (hot stamping line supplier), and Batz (tool manufacturer) has been initiated. The collaborative endeavour aims to conduct semi-industrial trials involving the hot stamping of an authentic automobile bumper employing high-strength 6xxx and 7xxx aluminum alloys. The hot stamping trials have been performed under different in-die quenching times and mechanical properties of the stamped bumpers have been empirically tested. These results have helped to define the optimal quenching time. With that aim, first, a thermophysical and rheological characterization of the aluminum has been performed, followed by the development of a model to predict mechanical properties of aluminum alloys. This predictive model, together with the aluminum material data, has been then integrated into the simulation framework to enable accurate forecasting of mechanical properties and, consequently, the identification of the optimal quenching duration. The results revealed that quenching times as brief as 1 second could be employed while maintaining acceptable mechanical properties in a rapid cycle hot stamping process. These expedited quenching times have the potential to boost production by an impressive 70 % when compared to the conventional hot stamping process applied to the equivalent steel bumper.

Optimizing friction stir processing parameters for aluminium alloy 2024 reinforced with SiC particles: A taguchi approach of investigation

The present investigation focuses on the microstructural behavior and mechanical properties of Aluminium alloy 2024 reinforced with SiC nanoparticles by applying the Friction Stir Processing (FSP) technique. Taguchi L9 orthogonal array was used to find the optimal process parameters. The experiment used the expected best process parameters, which confirmed the predicted highest value for the mechanical characteristic. Traverse speed, axial load, and rotating speed are the main factors affecting aluminum metal matrix composite. Hence, this experiment examined the effects of five different tool spinning speeds, specifically 800, 900, 1000, 1100, and 1200 rpm. Weld samples are fabricated wherein the stir zone contains SiC nanoparticles. The results of the study indicate that the optimal welding rotational speed of 1000 rpm has a significant impact on the microstructure, wear rate, and microhardness. Specifically, it was observed that the stirred zone exhibited enhanced wear resistance compared to other zones. The study's findings revealed that after implementing friction stir processing (FSP), a well-defined shear zone was observed on the advancing side of the stir zone. Additionally, it is found that the uniform dispersion and strong bonding of SiC particles with an aluminium matrix further enhance wear resistance.

The influence of La and Ce additions on the solidification of alloys from the Al–Fe system

AbstractAluminium alloys are popular in modern applications due to their lightweight, high strength and ductility. Alloys in the 8xxx series have similar properties to those in the 1xxx series, but are stronger, are more malleable and have higher stiffness. The addition of rare earths (RE) can refine the as-cast microstructure and, as a result, can increase the corrosion resistance and mechanical properties of aluminium alloys at room and high temperatures. The effects of rare earth (Ce and/or La) additions to Al-1.4Fe alloys were investigated. Thermal analysis of the solidification behaviour of the reference alloy showed the occurrence of three reactions corresponding to the formation of α-Al, eutectic (α-Al + AlxFey) and Fe intermetallics, respectively. The results showed similar reactions for the Ce- and/or La-modified alloy, but at slightly different temperatures, indicating a change in the forming phases due to the addition of Ce and/or La. In all cases, the microstructures were typically hypoeutectic, consisting of the primary α-Al and the eutectic (α-Al + AlxFey). The effect of grain refinement of the primary α-Al grains of the as-cast alloy was observed by the addition of RE, while La showed the strongest effect. The effect of the RE additions showed no obvious differences in the morphology of the eutectic AlxFey, although they were present in these phases. When Ce and/or La were added, (α-Al + Al11Ce3) and/or (α-Al + Al11La3) eutectics were formed, while Fe was not detected in these eutectics.

Improving Thermal and Mechanical Properties of CuـAl Based Alloy Used for High-Temperature Applications (A Review) By IJISRT

Despite the increased usage of composite materials, high-strength aluminum alloys maintain significance in airframe construction. Aluminum's attributes of being lightweight, relatively low-cost, heat- treatable, and capable of withstanding high-stress levels contribute to its continued importance. These properties also reduce manufacturing and maintenance costs compared to other high-performance materials. Recent advancements in aluminum aircraft alloys have enabled them to compete effectively with modern composite materials. This study delves into the latest developments, focusing on improving the mechanical properties of aluminum alloys and utilizing high-performance joining techniques. Cu-Al-based alloys represent a new class of functional materials. Due to their unique thermoelastic martensite structure, their exceptional damping performance has garnered attention in materials science and engineering. However, challenges such as elastic anisotropy and larger grain sizes can lead to brittle fractures, impacting the material's mechanical properties. It is widely acknowledged that achieving a finer grain size is pivotal when creating Copper Aluminum alloys with exceptional mechanical attributes and effective damping characteristics. Smaller grain sizes allow for the combined use of fine grain strengthening and interfacial damping, resulting in alloys demonstrating exceptional overall characteristics. This paper presents several standard approaches for preparing Copper Aluminum alloys, subsequently examining research efforts dedicated to enhancing grain size through alloying and heat treatment. Moreover, nanomaterials are being investigated as potential agents for reinforcing Cu–Al-based alloys, leading to substantial improvements in their mechanical characteristics and damping capacities. The study aims to serve as a valuable reference for future research in developing structure-function integrated materials capable of simultaneously offering high strength and high damping characteristics.

CHANGES IN THE STRUCTURE AND PROPERTIES OF ALUMINIUM ALLOYS WHEN MODIFIED WITH POWDER COMPOSITIONS

Purpose. To determine the effect of modification with powder compositions on the structure and mechanical properties of cast and deformed aluminium alloys. Research methods. Metallographic analysis, stereometric metallography, testing of strength and plastic properties of cast alloys AL4, AL4C of the Al-Si system and deformed alloys 1545 of the Al-Mg-Sc system, 2219 of the Al-Cu-Mn system in their original and modified state. Results. Meltings of AL4, AL4C, 1545, 2219 alloys were carried out in the initial state and with melt treatment with a complex nano-disperse modifier of magnesium silicide Mg2Si and silicon carbide SiC with a particle size of 50...100 nm. The optimal content of Mg2Si+SiC (0.10%) for increasing σ0.2 of aluminium alloys was determined. A 1.6-fold reduction in the grain structure of cast alloys was achieved. The dependence of the particle size and the amount of the modifier on the mechanical properties of the alloys was established. In industrial experiments, the most effective particle size of Mg2Si+SiC was established for increasing σ0.2 of AL4, AL4C alloy from 115 to 260 MPa in the as-cast state. The increase in the strength properties of the modified alloys is 44 % compared to the original state. Scientific novelty. Further development, insight into the influence of melt modification on the parameters of the structure and properties of aluminium alloys was obtained. The use of nanodispersed complex modifier Mg2Si+SiС with a particle size of 50...100 nm is proposed. It has been confirmed that the use of complex nanodisperse modifiers allows you to actively influence the structure and mechanical properties of aluminium alloys. Practical value. It has been experimentally proven that the rational amount of the introduced complex modifier is 0.10% of the mass of the melt. A significant grinding of the grain structure and an increase in the strength properties of cast and deformed aluminium alloys were achieved as a result of the modification.

Effect of post-weld heat-treatment and solid-state thermomechanical treatment on the properties of the AA6082 MIG welded joints

Post-weld heat treatment (PWHT) and solid-state thermomechanical treatment (TMT) via friction stir processing (FSP) have been shown to enhance the mechanical properties of aluminum alloys. The current work investigates the effects of PWHT and TMT on the microstructure and mechanical performance of AA6082-T6 welded butt joints welded using the MIG process. The 5 mm thick AA 6082-T6 plates were joined in butt configuration using MIG welding with ER 5356 filler wire, 120 A current, 0.3 mm/s weld speed, and argon shielding gas at 15 L/min flow rate. PWHT was performed on the MIG welds per the T6 temper procedure. TMT was implemented via FSP using a pinless tool rotating at 800 rpm and traversing speed at 200 mm/min with a 3° tilt angle. Microstructural analysis, hardness mapping, tensile testing, and fracture surface evaluation were utilized to characterize the as-welded, PWHT, and TMT samples. The results demonstrate that both PWHT and TMT significantly refine and homogenize the microstructures of the welded joints. However, the TMT samples displayed superior hardness and tensile strength compared to the as-welded and PWHT conditions. The TMT-processed welds achieved approximately 99% joint efficiency versus only 69% and 85% for the as-welded and PWHT samples. In summary, PWHT and especially TMT via FSP are effective at enhancing the mechanical properties of MIG welded AA6082-T6.

Influence of Nickel Percentage on Lattice Structure and Mechanical Strength in Al‐Si Alloy

Aluminum alloys play a crucial role in various industrial applications due to their low weight and favorable mechanical properties. The specific mechanical properties of aluminum alloys can be tailored through alloying and heat treatment processes to meet the requirements of different applications. This study focused on investigating the impact of Ni addition at different concentrations (0, 0.01, 0.05, and 0.1 wt. %) on the microstructure and mechanical strength of Al‐Si alloy. The evaluation was performed using X‐ray diffraction (XRD) and Vickers hardness (HV) tests. XRD analyses revealed that the Al‐Si alloy consisted of α‐Al and Si phases. Upon the addition of Ni, an intermetallic compound (IMC), Al3Ni, was identified. The presence of this IMC leads to changes in the lattice constant and interatomic spacing (dhkl). Vickers hardness (HV) measurements were performed on the samples before and after sintering. The results indicated that the highest hardness value obtained was 93 HV for the sample containing 0.1 wt.% Ni after sintering, whereas the lowest hardness value was 56 Hv for the sample without any nickel content before sintering. This increase in hardness can be attributed to the elevated temperature, which facilitated greater diffusion of nickel atoms into the aluminum lattice.

Experimental Investigation of the Effect of Die Shape on Mechanical Properties of Aluminum Alloy by Hot Direct Extrusion Process

This experimental study examined the impact of die shape on the mechanical characteristics of the AA7075, the aluminum alloy, extruded by hot direct extrusion. These characteristics include the extrusion load, hardness and compression tests, and stress-strain curve. Three alternative widths of the extruded metal exit zone (16, 18, and 20 mm) and three different die angles (15°, 30°, and 45°) were considered in the experiments. According to the findings, the extrusion load for the extruded items was the highest at an angle of 30° and the lowest at an angle of 15°. In terms of the hardness test of extruded materials specimens, the hardest areas were located at the outer circumference for all extrusion diameters and angles. Although the extruded samples’ compression test results showed variations in the samples’ loads before and after extrusion, it was also noticed that some of the other samples’ stress and strain curves converged while others had only slight differences.

Experimental Investigation of Effects of Manganese IV Oxide on the Mechanical Properties of Aluminium Alloy.

Aluminium and its alloys have proven to be highly valuable for a variety of technical applications due to its superior strength-to-weight ratio and exceptional corrosion resistance. As a result, there are numerous financial and environmental advantages to recycling it. The goal of this work is to significantly expand the engineering uses of recycled aluminium alloy by improving its mechanical characteristics by treatment with of MnO2. 30 kg of recyclable scrap aluminium alloy was initially acquired for the investigation in the form of ingots. Then, 5 kg of each was re-melted in three distinct samples. The first sample was re-melted and then left to cool naturally without any further intervention. 24g of dark powder from a dry cell thrown away was applied to the second sample, and 24g of MnO2 was applied to the third. Every sample underwent standard cooling procedures. The samples were then subjected to impact, tensile, and hardness testing by ASTM E8M-91 standard test protocols. The three samples were also subjected to XRD analysis. The sample treated with MnO2 had the highest hardness value, measuring 124 HV; the sample treated with powder from a discarded battery came in second, with 108.33 HV. With 99.30 HV, the control sample had the lowest value. The control sample had the highest UTS value of 92.74 MPa, the MnO2-treated sample had a UTS value of 68.23 MPa, and the sample treated with discarded battery powder had the lowest UTS value of 30.71 MPa. The control sample had the maximum impact strength value of 12.20 Joules, the discarded battery powder treated sample had an impact strength value of 11.96 Joules, and the MnO2-treated sample had an impact strength value of 11.32 Joules. The results of the study show that the recycled aluminium alloy becomes harder when MnO2 is added. Nevertheless, the inclusion of MnO2 shows a notable decline in the UTS of recycled aluminium alloy as well as a minor decrease in its impact strength.

The effect of cooling plate, mechanical vibration, and grain refinement on the microstructure and hardness of A380 produced by sand mold

ABSTRACT The mechanical properties of aluminium alloys can be increased by controlling the grain size and morphology of the alloy. In these studies, mechanical vibration, cooling slope plate (CSP), and grain refiner were applied on sand mould casting using A380 alloys. The hardness, and microstructure of the cast samples are investigated. These processes lead to the refinement of grain structures and a decrease in the tendency for dendritic structure formation. The Effect of the solidification time (modulus) on the microstructure is investigated. It was determined that the solidification time varies depending on the section thickness, which affects the SDAS values. It was observed that the lowest SDAS values were in CSP and the highest values were in grain refiners added casting. The lowest hardness value was recorded at CSP casting. Meanwhile, the grain refiner added vibration casting exhibits the highest hardness.

Changes in the structure and mechanical proper-ties of the aluminum alloy of the Al–Mg–Sc system as a result of treatment with a complex nanomodifier

Problem. On the basis of domestic and foreign research and the analysis of physicochemical properties of elements, the choice of scandium as a microalloying element of high-strength aluminium alloys is substantiated. The main criteria for the ability of scandium and its advantages over transition metals are given. Goal. The purpose of the work is to study the influence of a complex nanomodifier on the change in the structure and mechanical properties of aluminium alloy 1545 of the Al–Mg–Sc system. Methodology. For the first time, the treatment of aluminium melt with a complex nanodisperse modifier of the composition Mg2Si+SiС was proposed. The strength properties of aluminium alloys are significantly influenced by the size of the particles of the strengthening phase. Industrial experiments using dispersed particles of Mg2Si+SiС in a wide range of sizes of 50-100 nm. 
 Results. The technology of modifying aluminium melt with a complex modifier has been developed. Originality. A homogeneous structure of the modified alloy 1545 with a grain size 2.7 times smaller than the original state was achieved. Practical value. In the work, the grain size was determined and it was established that the grain size of alloy 1545 was 15.6 mm2 before modification, and 5.7 mm2 after modification. As can be seen from the given data, as a result of the modification, the grain structure of alloy 1545 was crushed by 2.7 times. It was established that the maximum values of σ0.2 and σv correspond to the optimal content of the powder composition: 0.10% with a further increase of the modifier, the strength properties decrease, while the increase in the strength properties of the modified alloy is 12...18% compared to the initial state.

Evaluations of low-temperature mechanical properties and full-range constitutive models of AA 5083-H112/6061-T6

The low-temperature mechanical properties of aluminium alloys (AAs) are important for the analysis and design of infrastructures in cold regions and LNG storage tanks made of AAs. This paper investigated the stress-strain behaviours of AA 5083-H112/6061-T6 materials through conducting tensile tests on 32 AA coupons at 20 ℃ ∼ −165 ℃. All the tested AA coupons exhibited ductile failure modes. Their results showed that the stress-strain curves of AA 5083-H112 exhibited the Portevin-Le Chatelier effects that gradually weakened with the decreasing temperature. Reducing the temperature from 20 ℃ to −165 ℃ increased the elastic modulus, yield and ultimate strengths of AA 5083-H112 (or 6061-T6) by 5.1% (6.5%), 8.7% (12.0%) and 7.8% (13.1%), but reduced the fracture strain by 16.4% (12.4%). The fracture surfaces of all AA 5083-H112 and 6061-T6 coupons displayed localised cross-sectional area reductions and substantial plastic deformation. Meanwhile, precipitation-hardened AA 6061-T6 exhibits a more pronounced enhancement compared to strain-hardened AA 5083-H112. Furthermore, regression analyses were performed to establish prediction equations for the low-temperature mechanical indexes of AAs. Subsequently, a full-range constitutive model was proposed to estimate the stress-strain behaviours of AA 5083-H112 and 6061-T6. Validations against reported experimental observations demonstrated that the developed model reasonably described the stress-strain responses of AA 5083-H112 and 6061-T6 from 20 ℃ to −165 ℃.