Experimental Study on Mechanical Properties of Aluminum Alloys under Uniaxial Tensile Tests (original) (raw)
Related papers
Experimental and numerical study on mechanical properties of aluminum alloy un.PDF
The main objective is to model the behavior of 7075 aluminum alloy and built an experimental database to identify the model parameters. The first part of the paper presents an experimental database on 7075 aluminum alloy. Thus, uniaxial tensile tests are carried in three loading directions relative to the rolling direction, knowing that the fatigue of aircraft structures is traditionally managed based on the assumption of uniaxial loads. From experimental database, the mechanical properties are extracted, particularly the various fractures owing to pronounced anisotropy relating to material. In second part, plastic anisotropy is then modeled using the identification strategy which depends on yield criteria, hardening law and evolution law. In third part, a comparison with experimental data shows that behavior model can successfully describe the anisotropy of the Lankford coefficient.
Evolution of Mechanical Behavior of Aluminum Alloy Al 7075 during Maturation Time
International Journal of Technology, 2016
The Aluminum 7075 (Al 7075) alloy is a precipitation hardening material instead of a strain hardening material. These mechanical properties are of a particular microstructure obtained by thermo-mechanical treatments. Among other things, this is a complicated microstructure which is responsible for the mechanical performance. The evolution of the mechanical properties of aluminum alloys is dependent on aging time parameters after heat treatment. In this study, the material has undergone a tempering heat treatment followed by a series of tensile tests. The experimental data (tensile curves in three directions during maturation time) is used to describe the evolution of the mechanical characteristics in terms of loading directions and maturation time, denoted respectively as: Ψ and t. The tensile curves are the source of data to begin the problem of identifying the behavior law of studied material using Barlat's model and Hollomon's isotropic hardening law. Thus, from the identified parameters (anisotropy coefficients and hardening coefficients), the evolution of the Lankford coefficient, deformation rate and load surfaces during the maturation time for three load directions (0°: rolling direction, 45° and 90°) are described. This study allows optimizing the response of the aluminum alloy to plastic strains, resulting from forming processes measured against the best time during maturation and the best load direction.
Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2018
The main purpose of this paper is to study the behavior of the 2000 aluminum alloy series used particularly in the design of Airbus fuselage. The characterization of the mechanical behavior of sheet metal on 2024 aluminum alloy and its response to various loading directions under monotonic and cyclic tests are extremely considered. To solve this problem, first, an experimental platform which essentially revolves around mechanical tests and then a series of optical and transmission electronic visualizations have been carried out. These mechanical tests are monotonic and cyclic shear tests applied under the same conditions on the test specimens of 2024 aluminum alloy. Cyclic shear tests have been carried out in order to show the Bauschinger effect and then the kinematic hardening phenomenon. The hardening curves of the simple shear test showed the Portevin-Le Chatelier effect for all loading directions. Next, the experimental results obtained (Portevin-Le Chatelier and Bauschinger effects) are discussed and analyzed in relation to the microstructure of the studied alloy using an optical microscope and a transmission electron microscope. Thereafter, the plastic anisotropy is modeled using an identification strategy that depends on a plastic criterion, an isotropic hardening law, a kinematic hardening (linear and nonlinear) law, and an evolution law. More precisely, particular attention is paid to the isotropic power Hollomon law, the saturation Voce law, and the saturation Bron law. In the case of the cyclic tests, linear kinematic hardening described by the Prager law and nonlinear kinematic hardening expressed by the Armstrong-Frederick law are introduced. Finally, by smoothing the experimental hardening curves for the various simple and cyclic shear tests, a selection is made in order to choose the most appropriate law for the identification of the material behavior.
"The analysis of the anisotropic behavior of materials has been the subject of various scientific studies, generally in the field of sheet forming processes of the aluminum alloys. The majority of the previous works search to define a mathematical description of the anisotropy starting from modified Hill yield criteria or using Cazacu-Barlat, Banabic or others sophisticated models. Many experimental studies report the anisotropic response analysis of aluminum alloys from the mechanical deformations obtained from uniaxial tensile tests, wire drawing or simple shear one and frequently starting from rolled thin sheets. However, there are relatively few studies concerning the anisotropic criteria corresponding to thick plate’s behavior caused by large plastic strain values. Then, in a first part of the chapter, will be presented the state of the art of the scientific studies in the field of aluminum alloys anisotropy. The both experimental and modeling points of view will be considered. In a second part, the aluminum alloys anisotropy and their mechanical behavior will be analyzed starting from the channel die compression tests. A rigorous analytical model, able to describe the large plastic deformation of the material specimen which occurs during this experimental test, will be developed. The main idea consist to define analytical equations which permits to compute the stress, the plastic strain rate and the cumulated plastic strain corresponding to a parallelepiped material undergoing a channel die upsetting loading. Final formulas will be established to compute all the coefficients corresponding to a Hill criterion. A comparison with the well known computation model corresponding to the tensile test will be made. Next, a more general Hill criterion, taking into account variation of its coefficients with the plastic strain, will be analyzed. Starting from the previous mathematical description, a general methodology, able to identify rigorously all the parameters defining the laws of variation of the computed quantities with the plastic strain, will be presented. Finally an application for a plan and normal anisotropic formulation, corresponding to a particular aluminum alloy rolled plate, will be detailed. A new approach will be then proposed in order to predict the Lankford coefficient values and a validation will be made by a comparison of these ones with those obtained from a classical tensile test. Numerical finite element analysis will be added to valid the proposed Hill criterion and the parameter identification procedure. In a final part the importance of the use of crystallographic texture for aluminum alloys characterization will be shown. The microstructure of the material will be determined through optical and SEM microscopy, EBSD and X ray measurements. In a more physical approach, using a micro-macro modeling, the relation between the macroscopic response of the material during the channel die compression tests and the active deformation slip systems will be analyzed in order to have a better understanding of the material anisotropy. References [1] R. Hill, Proc. R. Soc. Lond. A193, 281 (1948). [2] R. Hill, Math. Proc. Camb. Phil Soc., 85, (1979). [3] B. Plunkett, O. Cazacu, F. Barlat. International Journal of Plasticity, 24 (2008), p 847-866. [4] D. Banabic, K. Siegert, Anisotropy and formability of AA5182-0 aluminium of alloy sheets. CIRP Annals - Manufacturing Technology, 53, Issue 1, (2004), p 219-222. [5] H. Francillette, A. Gavrus, J-L. Béchade. “Study of the mechanical behaviour of zirconium 702 in correlation with the texture determined by X-ray diffraction”. Revue de Métallurgie, 12 (2003), p 1179-1183. [6] A. Gavrus, H. Francillette. Identification of anisotropic Hill criteria from the channel die compression test. Application to normal anisotropy of zirconium 702. Journal de Physique IV, 105 (2003), p11-18. [7] H. Francillette, A. Gavrus, R.A. Lebensohn. A constitutive law for the mechanical behavior of Zr702. Journal of Materials Processing Technology, 142 (2003), p 43-51. [8] A. Gavrus, H. Francilette. Formulation of anisotropic Hill criteria for the description of an aluminium alloy behaviour during the channel die compression test. American Institute of Physics (AIP) Conference Proceedings, 907 (2007), p 321-326. [9] H. Francillette, A. Gavrus, W. Chouikha. Caractérisation de l’anisotropie d’un alliage d’aluminium. Journées Annuelles de la SF2M, 17-19 Juin 2009, INSA de RENNES, France, Proceedings p. 232."
Study of the constitutive behavior of 7075-T651 aluminum alloy
International Journal of Impact Engineering, 2017
The flow and fracture behavior of 7075-T651 aluminum alloy has been studied under different stress-states, strain rate and temperature in order to explore the characteristics of the material under extreme situations developed in aerospace and armor structures. Influence of stress state was studied by performing quasi-static tension tests on notched specimens of different initial notch radii, 0.44 – 6 mm. Strain rate sensitivity was studied by carrying out tension test in the range 5 x 10-4 s-1 – 800 s-1. Thermal sensitivity of the material was studied by performing quasi static tension tests in the range 25 – 600 C. The increase in stress triaxility described increase in strength while reducing ductility. Increase in temperature on the other hand, stimulated opposite characteristics in the material. The variation in strain rate could not influence the flow and fracture behavior of material. Anisotropy observed in the material has been carefully investigated by carrying out tests in different in-plane and out of plane orientations. The stress-strain relations obtained through these tests were employed for calibrating Johnson-Cook (JC) flow and fracture model in different orientations. The Hill’s stress potentials were also obtained to incorporate the anisotropy in the material flow. Four different sets of parameters were calibrated and employed for numerically simulating the ballistic performance of 20 mm thick 7075-T651 aluminum targets against 12.7 and 7.62 API projectiles. The results thus reproduced through each set of parameters were compared with the experimental findings and the limitation and accuracy of each calibrated model have been discussed.
Hardening Model of Aluminum-Based Alloys After Conventional Plastic Deformation
METAL 2022 Conference Proeedings
The main objective is to model the plastic behavior of the three aluminum alloys 1050, 2024 and 7075.In the first part, using the experimental results of uniaxial tensile tests for each alloy and in the three main directions, and using a strategy of identifying the parameters of each work hardening model studied, Hollomon, Swift and Voce, we have created an empirical database of 1050, 2024 and 7075 aluminum series alloys.In the second part, one established the curves of uniaxial tensile curve by using the work hardening laws and the experimental parameters obtained in the first part. The comparison with the experimental data shows that the plastic behavior model can successfully describe with the use of appropriate workhardening law for each alloy.
Identification strategy of anisotropic behavior laws: application to thin sheets of Aluminium A5
Journal of Theoretical and Applied Mechanics
Numerical simulation provides a valuable assistance in the controlling of forming processes. The elasto-plastic orthotropic constitutive law is based on the choice of an equivalent stress, a hardening law and a plastic potential. An identification of the model parameters from an experimental database is developed. This database consists in hardening curves and Lankford coefficients of specimens subjected to off-axis tensile tests. The proposed identification strategy is applied to aluminum sheets. The behavior of this material is studied under several solicitations. The anisotropic behavior of the aluminum plate is modeled using the Barlat criterionand the hardening law. The obtained Lankford coefficients are compared to those which are identified by a different strategy.
Evaluation of Plasticity Models Using Uniaxial Tensile Test
European Mechanical Science, 2020
In this study, it is aimed to evaluate plasticity model prediction performance for plastic behavior of materials using a uniaxial tensile test. For this purpose, von Mises, Hill-48, Hill-93, Barlat-89 and Hu-2003 plasticity models are studied, and DC04, DP780, 6000 series aluminum alloy are used as materials. Tensile tests are performed with three directions (rolling, diagonal, transverse), and mechanical properties of materials are obtained. In addition, anisotropy coefficients of materials are calculated by uniaxial tensile tests. Validation of plasticity models is performed using obtained material parameters. Yield locus and yield stresses-anisotropy coefficients depends on directions are used in evaluation of plasticity models. As a result of this study, Hu-2003 showed the best modeling performance for all materials.
Characterization of the Plastic Behaviour of AA6016-T4 Aluminium Alloy
Advanced Engineering Forum, 2013
The current trend in the automotive industry consists in decreasing the weight of the car body to reduce the fuel consumption and the air pollution. This can be done by using low-density materials such as the aluminium alloys having good formability. A frequently used aluminium alloy in the manufacturing of the car body components is AA6016-T4. The paper presents a full mechanical characterization of this material with 1 mm thickness. The investigation starts by performing tensile tests on specimens cut at 0 o , 45 o and 90 o from the rolling direction. For each direction, the yield stress and the anisotropy coefficients are determined. The mechanical parameters of the Hollomon hardening law are determined using the experimental data obtained on samples cut along the rolling direction. Besides the uniaxial parameters, the equibiaxial yield stress and the equibiaxial coefficient of anisotropy are determined by performing bulge tests and compression tests, respectively. The yield surface is characterized in the first quadrant not only by the uniaxial and equibiaxial yield stresses but also by the yield stresses associated to the plane strain status. An experimental strategy for determining the plane strain parameters based on bulge tests is described in the paper. The characterization of the AA6016-T4 aluminium alloy ends with the determination of the forming limit diagram. The tests used for determining the limit strains are the punch stretching and hydraulic bulging.