Evolution of Mechanical Behavior of Aluminum Alloy Al 7075 during Maturation Time (original) (raw)
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Temperature and Strain Rate Effects on the Dynamic Strain Ageing of Aluminium Alloy AA7030
Materials Science Forum, 2006
The effects of temperature and strain rate on the mechanical properties of aluminium alloy AA7030 (Al-5.4Zn-1.2Mg) in naturally aged and peak aged condition are investigated, with emphasis on the relation to dynamic strain ageing. It is found that the naturally aged material shows more severe signs of dynamic strain ageing, including inverse strain rate and temperature dependence of flow stress, inverse temperature dependence of the ductility and serrated yielding. The peak aged material also shows signs of dynamic strain ageing, but to a lesser extent, most pronounced through serrated yielding. The observed effects can be qualitatively explained in terms of a thermal activation based model for dislocation glide. Furthermore, inhomogeneous deformation is observed on several size scales ranging from localized glide bands to surface deformation effects (orange peel surface) and macroscopic flow localization in shear bands.
Effect of Artificial Aging Temperature on Mechanical Properties of 6061 Aluminum Alloy
January 2019
Aluminum alloys have been attracted by several engineering sectors due to their excellent strengthweight ratio and corrosion resistant properties. These are categorized into 1, 2, 3, 4, 5, 6, 7and 8xxx on the basis of alloying elements. Among these 6xxx series contains aluminum–magnesium–silicon as alloying elements and are widely used in extruded products and automotive body panels. The major advantages of these alloys are good corrosion resistance, medium strength, low cost, age hardening response no yield point phenomenon and Ludering. 6xxx series alloys generally have lower formability than other aluminum alloys which restrict their utilization for wide applications. Keeping in view of the shortcomings in the set of mechanical properties of 6xxx series the efforts were made to improve the tensile strength and toughness properties through age hardening. In present study heat treatment cycles were studied for 6061 aluminum alloy. Three different age hardening temperatures 160, 200...
Effect of heat treatment on some mechanical properties of 7075 aluminium alloy
Materials Research
This paper reports the effects of annealing and age hardening heat treatments on the microstructural morphology and mechanical properties of 7075 Al alloy. The material was cast in the form of round cylindrical rods inside green sand mould from where some samples were rapidly cooled by early knockout and others gradually cooled to room temperature. From the samples that were gradually cooled some were annealed while others were age hardened. Both the as-cast in each category and heat treated samples were subjected to some mechanical tests and the morphology of the resulting microstructures were characterised by optical microscopy. From the results obtained there is formation of microsegregations of MgZn2 during gradual solidification which was not present during rapid cooling. It was also found out that age hardening and annealing heat treatment operation eliminated these microsegregations and improve mechanical properties of 7075 Al alloy. It is concluded that microsegregation can be eliminated by rapid solidification and appropriate heat treatment process.
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.
Influence of Intermittent Aging in AA7075 Aluminum Alloy
The Eurasia Proceedings of Science Technology Engineering and Mathematics, 2020
Heat treatable AA 7075 Aluminum alloys have been used especially in the aerospace industry for several years for their high specific strength. The demands in lighter aerospace or road vehicles like electric cars are today's major concerns. In this study, it is observed for how far the strength can be increased for this reason the influence of intermittent aging in AA7075 Aluminum alloy investigated. Rolled mill product of stock AA7074 Aluminum alloy samples were heat-treated for T6 conditions following a homogenization at 500 o C for 96 hours, and solution treatment at 500 o C for 4 hours and quenching in water. Aged at 120 o C for 24 hours and quenched. After the T6 heat treatment, an additional aging heat treatment so-called T6I4 was done at 100 o C for 2, 4, and 6 hours. The T6I4 heat-treated AA7075 alloys' microhardness values were incrementally increased by the intermittent aging heat treatment. The maximum increase rate was achieved with secondary aging at 100 o C for 6 hours, 51 % more according to the T6 condition.
METALLOFIZIKA I NOVEISHIE TEKHNOLOGII, 2019
In this study, the effect of the aging time on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment is investigated. The AA7075 alloys are quenched after solid solution treatment at 485°C for 2 hours and artificially aged at 120°C using five different aging times. Hardness measurements, microstructure examinations (SEM + EDS, XRD), and tensile tests are performed for the aged alloys. Fractured surfaces are also examined using SEM images after the tensile testing. The results of the studies conducted show that the hardness value of the alloys can be increased by increasing aging time, and the maximum hardness value of 192 HV is obtained for the alloy aged for 25 hours. Tensile tests also show that the tensile strength of the alloy can be increased by increasing aging time, and the maximum tensile strength value of 580 MPa is obtained for the alloy aged for 25 hours. Fractured surface examinations revealed that the ductile fracture mechanism is mostly dominant, while the planar fracture mechanism is observed as well.
Microstructure and Mechanical Properties of the AA7075T7352 Aluminum Alloy
Transactions of the Indian Institute of Metals
Microstructure evolution and their effects on mechanical behaviors of the AA7075T7352 aluminum alloy are reported. Phase analysis was done by X-ray diffraction and transmission electron microscope. The presence of the GP-Zones, ɳ', and ɳ, along with Al 2 Cu, Al 2 CuMg, and Al 3 Zr, was noticed. Mechanical characterizations were done with the help of a tensile test and Vickers microhardness. Flow behaviors were studied to evaluate the impact of second-phase particles in the properties. Strain hardening exponents along with UTS/YS ratio have been calculated. Flow curve fitting follows Ludwigson relationship with two distinct slopes. Dislocation loops and forest dislocation were noticed in the low strain range, while dense dislocation walls in the high strain range. Variation in flow parameters is due to the random spread of precipitate particles in the matrix. The material fails by mixed mode of ductile and brittle fractures.
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.
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.