AA6061 Aluminum Research Articles

Experimental study on machining of AA7075 using Taguchi method

AbstractThe machining parameter during milling process plays a very important role in the machining process of various materials. In this study the various parameters such as feed, speed of the spindle, depth of cut has been studied considering AA7075 aluminum material and its effect on surface roughness of the workpiece have been studied. These types of material are commonly used in aerospace, defense, marine and automotive industries due to its high strength to weight ratio. The optimization of these parameters has been done considering Grey-Taguchi method. From this study it can be concluded that good surface finish can be achieved during machining of AA7075 by controlling the various parameters. From the results it can be concluded that the cutting speed, feed is significant as compared to depth of cut.

Machine learning assisted investigation on properties of TiO2 reinforced aluminium metal matrix composites

The aim of this study is to investigate deeply about the properties of AA7075 aluminum alloy with varying stirring speed, temperature and different weight percentage of Titanium oxide reinforced with aluminum alloy using machine learning. Machine learning give consistent result with quantitative research.Taguchi method was effectively employed to find the optimal values of the input variables for the maximized values of hardness, impact strength and tensile strength. Stirring speed of 600 rpm, temperature of 600 °C and 9 wt% of TiO2 was finally found as the optimal parameters from this investigation. The model is perfectly fit as R square value is 99.5 %. The maximum brinell hardness is attained for the set of parameter (i) temperature 660 °C (ii) stirring speed 600 rpm and (iii) percentage of reinforcement is 6 wt%.

Investigation of microstructure and tribological properties of titanium-aluminide reinforced aluminum matrix composite friction surfaced on AA1050 aluminum

Abstract In this study, the microstructure and wear resistance of titanium-aluminide reinforced Al-Zn-Mg-Cu alloy matrix composite friction surfaced on AA1050 aluminum were investigated. The titanium-aluminide reinforced Al-Zn-Mg-Cu alloy matrix composite was fabricated using a semi-solid casting procedure at 630 °C. The results show that by increasing the consumable rod rotational speed from 800 to 1200 rpm, the width and height of the coating increased 15 and 16%, respectively, reaching 21.4 and 1.4 mm, respectively. The findings on the coating grain size show that the effect of plastic strain is dominant over the effect of temperature. Therefore, the coating grain size decreased by increasing plastic strain. By increasing the rotation speed from 800 to 1200 rpm, the coating hardness and shear strength values increase from 121.6 to 136.3 HV and 262.2 to 274.3 MPa, respectively. Also, the titanium-aluminide reinforcement does not have much effect on the thermal stability of the coating. After artificial aging heat treatment, TiAl intermetallic compounds, in addition to the Ti3Al intermetallic compounds, are formed in the coating. By applying the coating at a rotational speed of 1200 rpm, a traverse speed of 125 mm min−1, and an axial feeding rate of 75 mm min−1, the wear resistance of the substrate increased by up to 151%, respectively.

A new approach to flux deposition for brazing aluminium by low pressure cold spraying

Abstract This paper presents the results of study on the possibility of Nocolok flux deposition to aluminium substrates using the low-pressure cold gas spraying (LPCS) method. An innovative method of applying flux in the form of a powder without organic adhesive additives was proposed, allowing strict control of the deposited material. The influence of the flux powder feeding rate (PFR – 4.5 g/min, 6.3 g/min and 8.5 g/min) on the efficiency of the brazing process of AA3003 aluminium alloy plates was investigated. The results of energy dispersive spectrometry (EDS) analysis of the deposited flux coatings are presented for various process parameters. The wettability tested by spreading the B-AlSi12 filler metal on flux-covered aluminium substrates increased significantly with increasing PFR – the contact angle decreased from 21.0° to 4.6°. Microstructure analysis confirmed the high quality of the brazed joints, which were devoid of braze incompatibilities.

Recrystallization behavior and texture evolution on extrusion connection process of Mg/Al alloys thickness-oriented bonding sheet

Mg/Al alloys thickness-oriented bonding sheet extrusion is a new type of solid-state connection process for dissimilar metals, but metal flow during extrusion is complex, and the texture evolution law of the matrix on both sides is not clear. In this paper, the electron backscatter diffraction (EBSD) was used to observe the texture evolution and recrystallization behavior of the matrix on both sides of the extruded AZ31/AA6061 bonded sheets at different temperatures. Research indicates that AZ31/AA6061 has the highest bond strength (42 MPa) at T=390℃, and magnesium alloy has a lower texture intensity. The extrusion process of the thick bonded sheets will promote the dynamic recrystallization (DRX) of AZ31 magnesium alloy. When T=420°C, grain refinement is caused by both discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX). The {110} <113> texture intensity of AA6061 aluminum alloy gradually weakens with the increase of forming temperature, {110} <100> texture is enhanced instead, and the maximum pole density of the pole figure is decreased.

Effect of Single and Double Pulse MIG Welding Process Parameters on Microstructure and Properties of Aluminium Alloy

Lightweight aluminium alloys are widely used in many industries due to their advantageous mechanical properties. As welding is a popular method for joining aluminium alloy sheets, it is important to understand how the welding process affects the alloy’s performance. Here, we investigated the influence of various operating parameters during pulsed metal inert gas (MIG) welding of thin aluminium alloy plates on the input energy and metallurgical microstructure of the weld. A series of welding tests were performed using surface welding of AA6061 aluminium alloy plates under conditions of a single strong-pulse, single weak-pulse, or double pulse. The morphology, metallurgical structure, and hardness of the welds produced using the different welding parameters were then examined. We observed that increasing the welding speed and the arc duration of low-energy pulses can reduce the heat input. Lower heat input is advantageous as it results in a higher cooling rate of the welding pool and a smaller average grain size of the weld structure. In addition, increasing the welding speed increased the hardness of the weld. Double pulsed MIG welding showed the best overall weld performance and is recommended for improving the quality of aluminium alloy bonding.

Anticorrosion Superhydrophobic Surfaces on AA6082 Aluminum Alloy by HF/HCl Texturing and Self-Assembling of Silane Monolayer

In this paper, the tailoring of superhydrophobic surfaces on AA6082 aluminum alloy by chemical etching in an HF/HCl solution, followed by silane self-assembling, was applied for enhanced corrosion protection in the marine field. In particular, different etching times were considered in order to optimize the treatment effect. The results indicate that all the prepared surfaces, after silanization, were characterized by superhydrophobic behavior with a contact angle higher than 150°. The contact and sliding angles strongly depend on the surface morphology at varying etching times. The optimum was observed with an etching time of 20 s, where a microscale coral-like structure coupled with a homogeneous and ordered pixel-like nanostructure was obtained on the aluminum surface showing a Cassie-Baxter superhydrophobic behavior with a water contact angle of 180° and a sliding angle equal to 0°. All superhydrophobic surfaces achieved an enhanced corrosion protection efficiency and impedance modulus up to two orders of magnitude higher than the as-received AA6082 in simulated seawater.

Microstructure and residual stress modulation of 7075 aluminum alloy for improving fatigue performance by laser shock peening

Laser shock peening (LSP) is an advanced surface-strengthening technology that improves the anti-fatigue performance of metallic components. However, there is a significant barrier to the application of thin-walled components because the high-energy laser causes deformation and nonuniformity of compressive residual stress, thereby reducing fatigue performance. In this study, an LSP technology based on a low-pulse-energy laser was developed. We applied it to a thin-walled AA7075 aluminium alloy specimen (∼4 mm thickness) and achieved an improvement in the high-cycle fatigue limit of 20.4 and 37.0% for the smooth and pre-cracked fatigue specimens, respectively, in the absence of deformation. It was discovered that the enhanced dynamic nanoscale precipitation and dislocation multiplication effects of the high-pressure shock wave contribute to microstructure stability under cyclic loading, resulting in high compressive residual stress stability. Moreover, the unique heterogeneous grain structure on the surface layer subjected to LSP at low pulse energy effectively restrains crack initiation and propagation. Because these findings apply to a wide range of alloys, the current results create new avenues for improving the fatigue performance of thin-walled components.

Modeling of Probeless Friction Stir Spot Welding of AA2024/AISI304 Steel Lap Joint.

In the present study, AA2024 aluminum alloy and AISI304 stainless steel were welded in a lap joint configuration by Probeless Friction Stir Spot Welding (P-FSSW) with a flat surface tool. A full factorial DOE plan was performed. The effect of the tool force (4900, 7350 N) and rotational speed (500, 1000, 1500, 2000 RPM) was analyzed regarding the microstructure and microhardness study. A two-dimensional arbitrary Eulerian-Lagrangian FEM model was used to clarify the temperature distribution and material flow within the welds. The experimental results for the weld microstructures were used to validate the temperature field of the numerical model. The results showed that the tool rotation speed had an extensive influence on the heat generation, whereas the load force mainly acted on the material flow.

Finite Element Simulation and Experimental Investigation of Hot Forming Cold Die Quenching and Equal Channel Angular Pressing of AA2024 Aluminum Alloy

Finite Element Simulation and Experimental Investigation of Hot Forming Cold Die Quenching and Equal Channel Angular Pressing of AA2024 Aluminum Alloy

Mechanical properties optimization and microstructures of diffusion bonded AA2014/AA7075 al alloys

Diffusion bonding has been successfully used to join dissimilar high-strength aluminium alloys. In bonding AA2014 with AA7075 aluminium alloy, the main diffusion bonding process parameters were optimized to achieve optimum shear and ram tensile strengths. For the strategical planning of experiments, the design of experiment concept was used, as well as the response surface methodology to create statistical models for optimizing the process parameters. The bond strength improved as the interface thickness increased, but above 6 µm (at about 375 °C), the bond strength began to deteriorate. Similarly, the stiffness of the joint interface increased as the process temperature increased due to the development of interfacial phases. The empirical findings were evaluated, and the optimal bonding range was determined in order to maximize the bond’s shear and ram tensile strength.

An investigation on AA2024-15 wt%Cu composite cladded on AA1050 with superb mechanical and tribological properties

This study investigated the effect of pre-coating heat treatment and traverse speed of mechtrods on the microstructure, mechanical, and tribological properties of an AA2024-15 wt% Cu composite coating friction-surfaced on the substrate of an AA1050 aluminum. The findings indicated that increasing traverse speed during friction surfacing and using solid solutionized mechtrods lead to a greater agglomeration of copper particles. Using copper reinforcement improved the effectiveness of mechanisms such as particle stimulated nucleation that can help the grain size of the coating to be decreased. The distribution of copper particles was more non-uniform in the central regions compared to in the advancing and retreating sides. The precipitates and intermetallic compounds reduced the texture intensity in the coated samples. The AA2024-15 wt% Cu composite coating fabricated by AA2024-T3 rods showed average hardness and shear strength which increase up to 293% and 185%, respectively, compared to the substrate of an AA1050 aluminum. The wear rate of the AA2024-15 wt%Cu composite coating fabricated at a traverse speed of 100 mm/min decreased up to 27% and 23% compared to solid solutionized AA2024 and AA2024-T3 rods, respectively.

Effect of strain path and natural aging on the microstructure and hardness of AA7075 aluminum alloy

Effect of strain path and natural aging on the microstructure and hardness of AA7075 aluminum alloy

Ultrahigh-temperature aging response of asymmetrically cold-rolled AA2024 alloy

In this research, the effect of ultrahigh-temperature aging time on the microstructure and mechanical behavior of asymmetrically cold-rolled AA2024 aluminum alloy was studied. The cold-rolled samples were solution treated at 500 °C and aged at 500 °C for various times of 5, 10, 30, 60, 120, and 240 min. The microstructures, mechanical properties, and fracture surfaces of samples were investigated. It was found that by increasing the aging time, the elongated grains turned into equiaxed and coarser grains as well as the size and content of precipitates increased. The average hardness value increased up to 128 HV with increasing the aging time to 240 min. Also, the maximum yield strength (199.7 MPa) and ultimate tensile strength (384.4 MPa), as well as the minimum total elongation (20.8%), were achieved for the sample after 240 min of aging. The fracture surfaces of samples showed the ductile mode. The size of dimples increased and the number of dimples reduced with increasing the time of ultrahigh-temperature aging treatment.

Synthesis and Characterization of Borosilicate Glass Powder-Reinforced Novel Lightweight Aluminum Matrix Composites

Due to greater specific strength and stiffness than monolithic metal, aluminum matrix composite is in high demand. The present study investigated the interaction of borosilicate glass powder with the AA7075 aluminum alloy matrix. The lower density of borosilicate glass powder compared to AA7075 alloy makes the composite more appropriate for various industrial applications due to the increased material strength. This study uses the stir casting fabrication process to develop microsized borosilicate glass powder-reinforced aluminum matrix composites. The microstructure shows that borosilicate glass powder is near-uniformly distributed throughout the aluminum matrix. It is observed that the 9 wt (%) borosilicate glass powder-reinforced aluminum matrix composite increases the tensile strength by 40.71%, hardness by 21.21%, and impact strength by 34.37% compared to unreinforced aluminum AA7075 alloy. Pin-on-disc wear testing setup was used to determine the wear performance of the base AA7075 alloy and cast composites. The dry sliding wear test revealed that the glass powder-reinforced composites have better wear resistance properties compared to the unreinforced matrix due to the hard and rigid behavior of borosilicate glass reinforcement.

Effect of Natural Ageing on Subsequent Artificial Ageing of AA7075 Aluminum Alloy

The effects of natural ageing treatment prior to artificial ageing treatment on the microstructures and mechanical properties of AA7075 Al-5.7Zn-2.6Mg-1.5Cu-0.18Cr-0.08Mn-0.05Si-0.17Fe (wt.%) aluminum alloy have been investigated. The hardness of solution-treated samples (91.0 HV) profoundly increased to 146.8 HV after 7 days of natural ageing. The purpose of the present work was to examine the kinetic hardening evolution in subsequent artificial ageing treatments of samples naturally aged for 7 days and their counterparts without natural ageing. The former were labelled as NA-7d samples, and the latter, NA-0d samples. After artificial ageing at 120 °C for 2 h, the hardness of NA-0d samples increased rapidly to 148.2 HV, which was approximately the same as that of the specimens with natural ageing for 7 days, compensating for the prior state of lower hardness without natural ageing. After being treated at 120 °C for 16 h, the ultimate tensile strength (UTS) and yield strength (YS) of NA-7d reached the highest value, respectively, 601 MPa and 539 MPa, followed by a slight decrement of UTS when aged to 24 h. On the other hand, NA-0d specimens aged at 120 °C for 16 and 24 h showed nearly the same UTS (598 MPa); the former possessed YS of 538 MPa, and the latter, 545 MPa. The results presumably reveal that the peak ageing condition for NA-0d samples can be achieved under 24 h ageing at 120 °C. Under the same treatment at 120 °C for 24 h, the size of η’ phase in NA-7d sample (with a length of 4.96 nm) coarsened and grew larger than that in NA-0d sample (with a length of 3.46 nm). In addition, some η’ phase in the NA-7d sample was found to be transformed into the η2 phase. The results indicated that the naturally aged specimens (NA-7d) reached the peak ageing condition earlier, but did not significantly enhance the UTS in AA7075 aluminum alloy, as compared to the samples without prior natural ageing (NA-0d).

Microstructure and Crystallographic Texture in Twin-Roll Casting of AA1050 Aluminum Alloy: Simulation and Industrial Validation

Twin-roll casting (TRC) is a process in which liquid metal is introduced directly between counter-rotating water-cooled rolls, where it solidifies and is rolled to a strip having final thickness of 3 to 8 mm. TRC for aluminum is best suited to those alloys having a narrow freezing range with little susceptibility to hot tearing, such as 1XXX, 3XXX, 5XXX, and 8XXX. TRC offers advantages over conventional DC casting followed by hot and cold rolling for these alloys due to its lower capital cost, and decreased downstream processing operational cost and energy consumption, since hot rolling is not required. The microstructure formed in the strip must be carefully controlled, because as a near-net shape product used mostly for non-age-hardenable alloys, there is limited opportunity to modify it by subsequent processing. In particular, the near-surface microstructure has a strong effect on performance in forming applications. In this article, we present a computational model of TRC, and validate it for AA1050 aluminum alloy in a production environment. The novel aspect of this work is that the model is used to predict the final microstructure and crystallographic texture of the cast strip. The model is validated in plant trials for strip cast at a range of thicknesses, casting speeds, and caster setup by comparing the predicted microstructure, texture, and process outcomes such as roll separating force and forward slip to their corresponding measured values. We then apply the validated model to explore process parameters outside the standard practices, including feed inlet setback, casting speed, metal inlet temperature, and changing roll material to demonstrate how the microstructure and texture can be controlled via these parameters.

Application of MCDM and Taguchi super ranking concept for materials selection problem

Material selection is a topic of pivotal importance in the optimal design and development of industrial products. Increasing demand for high-performance materials with desirable and tailor-made properties is expected to drive the future market. This paper examines the application of multicriteria decision-making techniques like AHP, TOPSIS, EDAS, VIKOR, and Taguchi-based super ranking concepts for the selection of optimal aluminum alloy material for the sheet metal forming process. The criteria used to evaluate the optimal material selection were identified as yield strength, tensile strength, thermal conductivity, impact, density, specific heat, coefficient of thermal expansion, and % elongation. The most ranked aluminum material frequency is selected for sheet metal forming simulation using DEFORM, a process simulation FEM-based tool. An integrated Taguchi DOE and process simulation were carried out for the best-ranked AA2024 aluminum material. The results showed that the MCDM and Taguchi-based super ranking concept provides an intelligent and methodical assessment for solving material selection from a finite set of alternatives for the sheet metal forming process. The group decision behavior, agility, and flexibility in including multiple decision-making criteria for overall comparative analysis of materials, and manufacturing processes with uncertainty make MCDM methods a definitive tool for materials and manufacturing process selection.

Successful joining of ultra-thin AA3003 aluminum alloy sheets by the novel GTAW process

Joining ultra-thin aluminum sheets with the current welding technologies is very challenging because of the difficulty in controlling the heat input and the defect formation (thermal deformation). In this paper, the butt weld of 0.08-mm-ultra-thin AA3003 aluminum sheets was successfully performed utilizing the novel GTAW technology and the DCEN polarity mode. The results show that the weld bead has a good appearance with full penetration and free of hot tears or crack defects. Tensile samples were all fractured at the junction zone between the base-metal zone (BMZ) and the heat-affected zone (HAZ), confirming that the weld metal zone (WMZ) has the highest strength. The novel GTAW process with the novel collet's efficiency permits removing and blowing away the oxidation layer on the workpiece surface. Therefore, the welded joint has high quality without porosity and crack defects. This capability is a unique feature of the developed GTAW process compared to current welding technologies.

Tailoring the Microstructure of an AA5754 Aluminum Alloy by Tuning the Combination of Heat Treatment, Friction Stir Welding, and Cold Rolling

Friction stir welding (FSW) has now reached a technological impact and diffusion that makes it a common joining practice for several classes of metallic materials. These include light alloys (aluminum, titanium, magnesium), steels, and other metallic alloys. In addition, the combination of FSW with pre- or post-welding heat treatments or plastic deformation, such as cold rolling (CR), can favor minimal necessary plate thicknesses and induce effective alloy strengthening mechanisms that make the FSW joint lines as plate reinforcing zones. Process parameters, such as pin rotation and transverse speed, can be tuned to optimize the mechanical properties of the resulting joint. This work presents a microstructural study of the mechanical response of different sequences of heat treatment, FSW, and CR in a non-age hardened Al-Mg AA5754 alloy. By using polarized optical microscopy and microhardness tests, two FSW conditions were used to fabricate a joint; and were than subjected to different sequences of heat treatment and cold rolling. The results suggest that FSW conditions have a limited effect on the microstructure, while microhardness profiles show a higher variability of the different datasets related to the low welding speed investigated.