Aluminum Alloy Al7075 Research Articles

Toolpath and Tool Design Innovations in Deformation Machining for Superior AA-7075 T6 Fins

Abstract A hybrid manufacturing process, deformation machining (DM) combines subtractive manufacturing with incremental forming. Monolithic components with complex profiles are created through the hybridization of manufacturing technologies, which also reduces the wastage of raw materials. The properties of geometry and surface quality of the fin made from the aluminum alloy Al-7075 T6 using the DM process’s bending mode was examined in this research, as were the effects of various approaches, toolpath methods, and tool design. To achieve the desired shape for the machined fin, various combinations of arcuate and slanting fin toolpath techniques were explored utilizing both top-down and bottom-up methods. The bottom-up method and the arcuate toolpath strategy were used to investigate various tool profiles. Using the best combination of toolpath strategy and tool profile, named as the T3 tool profile, which has a 0.6 mm nose radius and a circular sector, bottom-to-top (BTT)technique, and arcuate toolpath method, components with better geometrical features and surface roughness (SR) were produced. The analysis of the forming force in the bending approach of the DM progression was further carried out using this optimal combination.

Modeling of milling forces in facing process of aluminum alloy AL7075 using the square inserts

Cutting forces play very important in designing the tool machine, cutting tool, and in optimization of machining processes. Modeling and prediction of cutting forces by theoretical methods are quite difficult, so, this study was focused on modeling the cutting force in face milling process using combination of theoretical and experimental methods. This study was performed to model the milling forces (MFs) and determine the milling force coefficients (MFCs) in the face milling process of aluminum alloy Al7075 using square inserts. From theoretical and experimental methods, the relationship of average milling forces (AMFs) and feed per flute (ft) were determined as the linear regression. Using experimental data, the linear regressions of AMFs and feed per flute were determined with high values of determination coefficients (larger than 95 %). MFCs were determined including shear and edge MFCs (tangential shear MFC (Ktc) of 538.127 N/mm2, radial shear MFC (Krc) of 185.967 N/mm2, axial shear MFC (Kac) of -691.297 N/mm2, tangential edge MFC (Kte) of 11.253 N/mm, radial edge MFC (Kre) of 6.991 N/mm, and axial edge MFC (Kae) of –32.971 N/mm. The MF models were successfully verified by comparing the measured and predicted MFs in face milling process of Al7075. The tendency and shape of predicted MFs were quite close to the measured ones. The differences between the predicted and the measured MFs can be due to the several reasons such as the influence of vibrations, the influence of cutting heat, etc., and these are also the limitations of this study. The modeling and prediction methods of this study can be used to model and predict the cutting forces in face milling of other milling types and other pairs of cutting tool and workpiece material as well

Surface texture analysis in polycrystalline alloys via an artificial neural network

Surface finish has a significant impact on the properties (e.g., fatigue strength and corrosion resistance) of manufactured products; consequently, industries seek to quantitatively evaluate the surface finish of their products. The surface finish of test specimens, made of the aluminum alloy AL7075−T6, has been measured with a confocal microscope, where the ensemble of collected experimental data has been analyzed by the following four methods of surface texture quantification: (i) arithmetical mean height Sa; (ii) root mean square height Sq; (iii) maximum height Sz; and (iv) ten-points height S10z. This paper addresses automated prediction of surface quality by an artificial neural network (ANN) that has been used to classify the analyzed values of surface textures based on the concept of pattern recognition. The best surface textures are determined by relying on the performance of the ANN model, which depends on the accuracy, precision, recall, and F1-score of the test data. The results show that, for small variations in surface finishing, the test method S10z most accurately predicts quality of surface textures, which is followed by the test method Sa.

Experimental investigation on tool pin profile for defect-free multi-layered laminates using friction stir additive manufacturing

Friction stir additive manufacturing (FSAM) is a sub-set of solid-state additive manufacturing technique that falls under sheet lamination additive manufacturing. This technique employs friction stir welding (FSW) to produce large, multi-layered parts via the plate addition method. Sufficient heat generation and material mixing are the basic requirements of FSAM, which are primarily dependent on the tool pin profile and the optimal selection of process parameters. Therefore, three tools with distinct pin profiles were selected (plain cylindrical, cylindrical threaded, and taper threaded) at variable tool transverse speeds (20, 40, 60 mm/min). The current study investigates the influence of pin profile and welding speed on material mixing and heat generation, specifically in terms of defects produced between the bonded layers of aerospace aluminum alloy Al-7075. A tool rotational speed of 500 rpm and 1200 rpm with a tool tilt angle of 2.5° were employed for all three tools to develop a 4-layered laminate. It was observed that among all, taper threaded tool pins produced defect-free laminates at 500 and 1200 rpm for all three welding speeds. This was attributed to the higher microhardness with grain size ranging from 0.96 μm to 1.47 μm. Overall, a 95.61 % reduction in grain size was achieved using the taper threaded tool pin profile compared to the as-received base material. Microhardness was enhanced with the increase in transverse speed and building height, furtherer highlighted with statistical analysis.

Waist-Supportive Exoskeleton : Systems and Materials

Waist-supportive exoskeletons have been designed and developed to lower the possibilities of spinal injuries of workers working in different fields like assembly lines, logistics, construction, healthcare, and agriculture. It is preferable to utilize an external wearable device for the human workers which will enhance their capabilities in certain areas of industries where heavy load lifting machines like forklifts and stackers cannot be utilized in compact spaces. This article discusses the systems of waist supportive exoskeleton and reviews the material selection aspects for manufacturing frame of the exoskeleton. Aluminium alloy Al7075 and Carbon Fibre are more suitable for manufacturing frame of the waist-supportive exoskeletons. Design of exoskeleton can be further improved by using composite materials for its various components which will reduce its overall weight and enhance human capabilities.

Multi-Criteria Selection of the Optimal Parameters for High-Speed Machining of Aluminum Alloy Al7075 Thin-Walled Parts

Thin-walled parts made of aluminum alloy are mostly used as structural elements in the aerospace, automobile, and military industries due to good homogeneity, corrosion resistance, and the excellent ratio between mechanical properties and mass. Manufacturing of these parts is mainly performed by removing a large volume of material, so it is necessary to choose quality machining parameters that will achieve high productivity and satisfactory quality and accuracy of machining. Using the Taguchi methodology, an experimental plan is created and realized. Based on its results and comparative analysis of multi-criteria decision making (MCDM) methods, optimal levels of machining parameters in high-speed milling of thin-walled parts made of aluminum alloy Al7075 are selected. The varying input parameters are wall thickness, cutting parameters, and tool path strategies. The output parameters are productivity, surface quality, dimensional accuracy, the accuracy of forms and surface position, representing the optimization criteria. Selection of the optimal machining parameter levels and their ranking is realized using 14 MCDM methods. Afterward, the obtained results are compared using correlation analysis. At the output, integrative decisions were made on selecting the optimal level and rank of alternative levels of machining parameters.

Measurement of Friction and Wear in Aluminum Alloy Al7075/Sic & Gr Processed By Friction Stir Method

Aluminum proved its effective usage in various applications because of its light weight and high strength. This work highly focused on fabrication of aluminum alloy Al7075 with addition of (10 wt. %) of silicon carbide (SiC) and (10 wt. %) graphite (Gr) by using friction stir processing. Initially reinforcement distribution examined by using SEM and EDS analysis. Co efficient of friction and wear was examined by pin on disc Tribometer. Based on the experimental results, improved mechanical properties and tribological properties were obtained compare to the base metal Al7075 aluminum alloy.

Evaluation on advantages of low frequency assisted drilling (LFAD) aluminium alloy Al7075

Evaluation on advantages of low frequency assisted drilling (LFAD) aluminium alloy Al7075

Effect of Nickel Reinforcement on Micro Hardness and Wear Resistance of Aluminium Alloy Al7075

Presently, wear resistance of aluminium alloys have gained a greater importance in various industrial applications. Research works regarding strengthening of aluminium alloys introduced a new class of composites, i.e. aluminium intermetallic composites. Aluminium alloy Al7075 with zinc as the major alloying element is widely used in various industrial fields, and there is a research scope in fabricating Al7075-Al3Ni intermetallic composites by reinforcing nickel particles. In this study, four composites of different weight percentages (i.e. 1%, 5%, 10%, and 15%) of nickel and base alloy were fabricated by using stir casting method. After fabrication, the materials were subjected to T6 heat treatment. The micro hardness evaluation of the composites before and after the heat treatment was performed, and compared with the base alloy. Micro hardness of base alloy was improved up to 146% by reinforcing 15% nickel followed by the heat treatment. Wear rate of heat treated base alloy and composites was studied. Heat treated Al7075+15% nickel composite shows more wear resistance (about 93% resistant than heat treated base alloy). The wear properties of heat treated Al7075+15% nickel composite was studied at different applied loads and sliding velocities.

Evaluation on advantages of low frequency assisted drilling (LFAD) aluminium alloy Al7075

Drilling operation of dissimilar stack materials is a crucial assembly operation in airframe manufacturing; this is due to both the number of holes drilled in an aircraft structure and the fact that this is an operation performed in the finishing phase of the manufacturing chain. This paper aims to evaluate an alternative strategy for conventional drilling and peck drilling, which are now the most widespread solutions used for drilling aluminium alloys. The alternative approach proposed by this paper consists of low frequency assisted drilling (LFAD) performed into frequencies vibrations (between 50 to 100 Hz). In this paper, the chip formation process of drilling assisted by low-frequency vibrations of FC/Al stack material has been analytically modelled and compared with the conventional drilling of aluminium. Results show chip segmentation during the drilling operation resulting in less temperature increasing, avoiding problems in the final geometrical quality of the hole, and burr formation.

Environment effect on microstructure properties of gas tungsten arc welding for titanium and aluminium alloy joints

Many engineering applications are in need of high strength and low weight alloys; titanium and aluminium alloys areused in several engineering applications to reduce weight. In this study, investigate effect of environment conditions onmicrostructure properties of gas tungsten arc welded assisted with brazing of titanium alloy Ti-6Al-4v and aluminium alloyAl7075 has been carried out. Alloys are made joined together in natural environment and at shielded argon gas environmentconditions. Mechanical properties have been arrived, tensile tests have been conducted to examine the strength of weld andresults have been achieved 92.3 Mpa and 356 MPa in regular and argon environment, respectively. Vicker’s hardness valueof 103.4 Hv and 183.1 Hv has been attained in respective environment condition. Fatigue properties have been elevated andfracture surface of the specimens analyzed in respective mechanisms. Welding speed, arc voltage and welding currentparameters are considered to join the dissimilar alloys in both environments and identified the most influencing parameters.SEM and XRD techniques have been used to weigh up the microstructures of weld interface. The outcomes confirmed thatargon gas, as a joining environment, has a substantial blow on properties of mechanical and microstructure of the weld joint.

Numerical Study of Energy Absorption Behaviour of Thin Aluminium Hemispherical Shell against Projectile Impact

Abstract The paper presents finite element investigation to explore the performance of the 1mm thick aluminium alloy [Al-1100, Al-7075, Al-6065 and Al-2024] hemispherical shell target struck by ogive nose projectile. The ogive nose projectile of length 50.8 mm, diameter 19 mm and mass 52.5g was hit at the tip of the shell with varying incidence velocity. The numerical analysis was conducted in ABAQUS/Explicit software using Johnson-Cook model. The ballistic impact response of thin shells was analysed by computing the ballistic limit, residual velocity and global deformation for different alloys. Result showed that ballistic limit is highest for aluminum alloy Al-7075

Experimental Investigation on Mechanical and Wear Properties of Al7075-B<sub>4</sub>C-TiO<sub>2 </sub>Composite

Hybrid metal matrix composites are being widely investigated for use in light weight, high strength applications. In the present study, Aluminium alloy Al7075 was reinforced with B4C and TiO2at 4% and 2% weight fractions respectively. The powders of the reinforcements were ball milled for uniform distribution in the Al matrix, and later fabricated by stir casting technique primarily due to simplicity and economy of the method. The specimen were prepared as per ASTM standards and later subjected to hardness, double shear, wear and impact tests and the results were compared with that of pure aluminium specimen fabricated by the same method. The hardness, shear strength, impact strength of the composite were found to be higher than pure aluminium by 4.97%, 32.28% ands 6.41% respectively.

Robust modeling and optimization of borehole enlarging by helical milling of aluminum alloy Al7075

The paper aims to analyze the use of helical milling in hole enlargement in aluminum alloys, considering the effects of the input variables (tool overhang, cutting speed, axial and tangential feed per tooth) on the output ones related to the hole quality such as radial force, circularity and roughness. Additionally, the robust optimization is developed through the combination of robust parameter design, mean square error, and normal boundary intersection through responses modeled by response surface methodology. The results show that hole enlargement by helical milling is feasible and could achieve good values of radial forces, circularities, and specially roughness, which presented average roughness values under 0.2 μm for all experiments. The observed relationship between input and outputs shows that the axial and tangential feed are significant for all responses in linear, quadratic, and interaction terms, and cutting speed and tool overhang have at least significant terms in linear, quadratic, or interaction models. Low values of axial feed per tooth reduce radial force and circularity. Tool overhang is a noise variable and is directly connected to the shape error, since high values increase circularity deviations. Since significant noise terms exist, the robust optimization was able to reduce the variability of tool overhang in the responses and achieve mean values of circularity, radial forces, average and total roughness of about 7 μm, 20 N, 0.1 μm, and 1.7 μm, respectively.

A Study of Tribological Behaviour of Aluminum-7075/SiC Metal Matrix Composite

The present work investigates thetribological behaviour of aluminium alloy Al-7075 reinforced with silicon carbide particles (10% & 15% weight percentage of SiC) fabricated by stir casting process The wearand frictional properties of the metal matrix composites was studied by performing dry sliding wear test using a pin-on-disc wear tester. Experiments were conducted based on the plan of experiments generated through Taguchi’s technique.ATAGUCHI L-9 Orthogonal array was selected for analysis of the data. Investigation to find the influence of applied load, sliding speed and sliding distance on wear rate, as well as the coefficient of friction during wearing process was carried out using ANOVA and regression equation for each response were developed for both 10% & 15% SiC reinforced Al-7075 MMCs. Objective of the model was chosen as “smaller the better” characteristics to analyze the dry sliding wear resistance.Results show that sliding distance has the highest influence followed by load and sliding speed. Finally, confirmationtests were carried out to verify the experimental results. The regression analysis is successfully employed to predict the wear rate and coefficient of friction for both the weight ratios of composite. However, 10 wt.% composite is predicted with highest accuracy of 95.2% followed by the 15 wt.% composite with 93.4%.

Effect of cryogenic milling on Al7075 prepared by spark plasma sintering method

Precipitation of secondary intermetallic phases in aluminium alloy Al7075 sintered by spark plasma sintering method from powders milled at room and cryogenic temperature was studied by X-ray powder diffraction. Deformation energy stored during cryogenic milling influences the precipitation in Al7075 alloy. High temperature X-ray diffraction experiment revealed the potential for further precipitation strengthening of samples prepared by spark plasma sintering of milled powders. It was established that the correction of absorption edge of metal Kβ-line filter used for laboratory sources greatly enhances the precision of quantitative Rietveld analysis as well as the determination of precipitates’ crystallite sizes.

Crack Paths at Multiple-crack Systems in Anisotropic Structures: Simulation and Experiment

This paper is targeted on numerical methods for accurate crack tip loading analysis and crack path prediction. Those are based on finite element calculations of the boundary value problem. Applying path-independent integrals to curved cracks in order to accurately calculate the J-integral, energy release rate (ERR) or stress intensity factors (SIF) is still not state of the art. Contours which are not confined to the crack tip require special analytical preparation and numerical treatment to supply results which are sufficiently precise for reliable crack path prediction. Methods to improve the calculation of the J-integral and the interaction inte- gral (I-integral) are presented. In particular, the latter has never been applied to strongly curved cracks. Also, efficient methods for the loading analysis and crack growth simulation of multiple interacting cracks based on path-independent integrals are presented. The anisotropy of fracture toughness is taken into account being a crucial part of the numerical model. Experiments are carried out with specimens made of aluminum alloy Al-7075, comparing subcritically grown cracks with simulations.

Numerical and Experimental Investigation of Crack Parameter Identification in Elastic Plate Structures based on Remote Strain Fields

In this work two different methods for the detection of cracks in plate structures are presented. In fact, the methods exploit strains measured at different locations on the surface of a structure. Solving the inverse problem, this allows both the identication of crack position parameters, such as length, location and angles with respect to a reference coordinate system and the calculation of stress intensity factors (SIF). First, the solution of the direct problem is obtained e.g. by using the BFM (body force method), substituting the crack by distributed point loads leading to strain fields by superposition of fundamental solutions. On the other hand, the dislocation technique is applied particularly to bounded structures and inclined crack paths. The inverse problem is solved applying the particle swarm optimization (PSO) algorithm. Experiments are performed under cyclic loading using pre- cracked plates made of the aluminum alloy Al-7075.

On the Point Method and the Line Method notch effect predictions in Al7075-T651

The Point Method and the Line Method are two approaches derived from the Theory of Critical Distances, used in conjunction with a characteristic material length parameter when performing fracture assessments on any kind of stress risers, including notches. This paper analyses the application of both the Point Method and the Line Method for the prediction of the notch effect on the aluminium alloy Al7075 in T651 conditions. The parameters involved in the analysis are calibrated through a combination of experimental tests and finite elements modelling, and a comparison is made between the experimental results and the predictions provided by these two approaches. Also, a Scanning Electron Microscopy analysis is performed, establishing relations between the fracture mechanisms and the predictions provided by the Theory of Critical Distances. The results obtained demonstrate the suitability of the Point Method and the Line Method for the analysis of notches.

Electrochemical corrosion behavior of Al7075 rotating disc electrode in neutral solution containing l-glutamine as a green inhibitor

This is a study of the electrochemical corrosion behavior of aluminum alloy Al7075 and its corrosion inhibition using l-glutamine in 3.5% NaCl solution under different hydrodynamic conditions. The hydrodynamic conditions were simulated by using a rotating disc electrode. The results showed that an increase in rotation speed leads to a higher corrosion current density, while the charge transfer resistance decreases and corrosion potential shifts toward more positive values. The inhibition efficiency depends on rotation speed. That is, the efficiency was low in stagnant solution, but enhanced significantly under hydrodynamic conditions. The phenomenon was attributed to the increased mass transport of inhibitor’s molecules to the electrode surface that is advantageous for improvement of inhibition efficiency. However, higher rotation speeds (Ω ≥ 1,500 rpm) cause a slight reduction of efficiency due to higher shear stresses.