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1
Wu, Linda, and W. George Ferguson. "Modelling of Precipitation Hardening in Casting Aluminium Alloys." Materials Science Forum 618-619 (April 2009): 203–6. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.203.
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Precipitation hardening, or aging hardening, is one of the most widely adopted techniques for strengthening of aluminium alloys. During the precipitation process, three major mechanisms are involved: i.e. nucleation, growth and coarsening. Kampmann and Wagner have developed a powerful and flexible numerical approach (KWN model) for dealing with concomitant nucleation, growth and coarsening and thus capable of predicting the full evolution of the particle size distribution. KWN model has been successfully applied to a number of aluminium alloy systems, such as 2xxx, 6xxx and 7xxx. However, most of these modelling works were focused on the wrought aluminium alloys, few had applied to the casting aluminium alloys. In the present modelling work, the microstructure evolution is modeled based on the KWN model and then a strength model based on the well established dislocation theory is used to evaluate the resulting change in hardness or yield strength at room temperature. Then the modelling is applied to casting aluminium alloys A356 and A357. And the modelling results are validated by comparing with own experimental results and the results obtained from the open literature.
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Ji, Kang, Guanfeng Li, Yongbao Sun, et al. "A Constitutive Model for Yield Strength and Work Hardening Behaviour of Aluminium Alloys during Artificial Ageing." Metals 10, no. 8 (2020): 1094. http://dx.doi.org/10.3390/met10081094.
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In this study, a unified constitutive model has been developed for both yield strength and work hardening behaviour prediction of aluminium alloys with different types of precipitates during and after artificial ageing. The different type and dimensions of general precipitate shapes (sphere, plate, rod) have been classified and modelled by a primary dimension and aspect ratio, with which a general set of equations has been utilised to model the precipitates evolutions during ageing of various aluminium alloys. In addition, the effects of main microstructures on not only yield strength but also work-hardening behaviour of artificially aged aluminium alloys have been considered and modelled, based on which, a whole set of unified constitutive model considering both micro- and macro-properties for long-term artificial ageing of aluminium alloys has been proposed. Artificial ageing of two representative aluminium alloys (an Al-Mg-Si alloy AA6063 and an Al-Cu-Li alloy AA2198) has been adopted to show the capability and effectiveness of the developed model. The results show that the model can successfully predict the microstructures, yield strength and work hardening behaviour of various aluminium alloys with different precipitate types after long-term artificial ageing process, e.g., from 0 h to 500 h. It is believed that the model can be used for ageing of other aluminium alloys with dominant sphere, plate or rod-shaped precipitates.
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Reich, Michael, S. Schöne, O. Kessler, et al. "Simulation of Gas and Spray Quenching during Extrusion of Aluminium Alloys." Key Engineering Materials 424 (December 2009): 57–64. http://dx.doi.org/10.4028/www.scientific.net/kem.424.57.
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After the extrusion process most aluminium alloy profiles don´t satisfy the necessary strength requirements. An increase of strength can be obtained by age hardening of hardenable aluminium alloys. Age hardening includes the three steps of solution annealing, quenching and aging and is usually carried out in a separate process after extrusion. The integration of the sub-steps solution annealing and quenching in the extrusion process results in a marked reduction of the complete process chain. The applicability of this integration depends primarily on the quenching power of the cooling module and on the quench sensitivity of the aluminium alloy. Using the finite element method the non-steady-state process of quenching the profiles after leaving the extrusion press has been simulated. The boundary conditions for quenching are varied for a gas nozzle field and a spray cooling using heat transfer coefficients based on experiments. The simulation results support the design of gas nozzle fields or spray cooling for the extrusion process of different aluminium alloys.
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Su, Mei Ni, Ben Young, and Leroy Gardner. "Continuous Strength Method for Aluminium Alloy Structures." Advanced Materials Research 742 (August 2013): 70–75. http://dx.doi.org/10.4028/www.scientific.net/amr.742.70.
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Aluminium alloys are nonlinear metallic materials with continuous stress-strain curves that are not well represented by the simplified elastic, perfectly plastic material model used in many current design specifications. Departing from current practice, the continuous strength method (CSM) is a recently proposed design approach for non-slender aluminium alloy structures with consideration of strain hardening. The CSM is deformation based and employs a base curve to define a continuous relationship between cross-section slenderness and deformation capacity. This paper explains the background and the two key components - (1) the base curve and (2) the strain hardening material model of the continuous strength method. More than 500 test results are used to verify the continuous strength methodas an accurate and consistent design method for aluminium alloy structures.
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Westermann, Ida, Odd Sture Hopperstad, Knut Marthinsen, and Bjørn Holmedal. "Work- and Age-Hardening Behaviour of a Commercial AA7108 Aluminium Alloy." Materials Science Forum 618-619 (April 2009): 555–58. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.555.
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Understanding and prediction of the mechanical properties of aluminium alloys are of great importance with respect to e.g. strength requirements and forming operations. In the 7xxx alloying system several mechanisms influence the hardening behaviour of the alloys, e.g. particle size and distribution, dislocation density, and alloying elements in solid solution. This work is an experimental study of work- and age-hardening considering a commercial AA7108 alloy in the as-cast and homogenized condition. Tensile specimens have been exposed to a solution heat treatment and a two-step age-hardening treatment with varying time at the final temperature. The tensile data for the different tempers have been evaluated in elucidation of already existing models based on the one-parameter framework by Kocks, Mecking, and Estrin. The particle size has been further investigated in the transmission electron microscope for one under- and one over-aged condition and the influence of particles on work-hardening behavior has been discussed.
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Schäfer, C., Mischa Crumbach, and Günter Gottstein. "Modelling Nucleation of Recrystallisation in Aluminium Alloys." Materials Science Forum 550 (July 2007): 85–94. http://dx.doi.org/10.4028/www.scientific.net/msf.550.85.
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The predictions from a grain cluster deformation texture model, GIA, are utilized to study the nucleation texture of recrystallisation of aluminium alloys. In combination with a dislocation based work hardening model, the propensity of specific grains in their granular environment for select nucleation mechanisms is investigated. Quantitative criteria for the nucleation events can be formulated. The results can be fed into a growth model of recrystallisation to predict recrystallisation textures and lend themselves to through-process modelling.
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Fröck, Hannes, Lukas Vincent Kappis, Michael Reich, and Olaf Kessler. "A Phenomenological Mechanical Material Model for Precipitation Hardening Aluminium Alloys." Metals 9, no. 11 (2019): 1165. http://dx.doi.org/10.3390/met9111165.
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Age hardening aluminium alloys obtain their strength by forming precipitates. This precipitation-hardened state is often the initial condition for short-term heat treatments, like welding processes or local laser heat treatment to produce tailored heat-treated profiles (THTP). During these heat treatments, the strength-increasing precipitates are dissolved depending on the maximum temperature and the material is softened in these areas. Depending on the temperature path, the mechanical properties differ between heating and cooling at the same temperature. To model this behavior, a phenomenological material model was developed based on the dissolution characteristics and experimental flow curves were developed depending on the current temperature and the maximum temperature. The dissolution characteristics were analyzed by calorimetry. The mechanical properties at different temperatures and peak temperatures were recorded by thermomechanical analysis. The usual phase transformation equations in the Finite Element Method (FEM) code, which were developed for phase transformation in steels, were used to develop a phenomenological model for the mechanical properties as a function of the relevant heat treatment parameters. This material model was implemented for aluminium alloy 6060 T4 in the finite element software LS-DYNA (Livermore Software Technology Corporation).
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Faggiano, Beatrice, Gianfranco De Matteis, Raffaele Landolfo, and Federico M. Mazzolani. "BEHAVIOUR OF ALUMINIUM ALLOY STRUCTURES UNDER FIRE." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 10, no. 3 (2004): 183–90. http://dx.doi.org/10.3846/13923730.2004.9636305.
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In the paper the attention is focused on the influence of high temperatures on the mechanical properties of the aluminium alloys selected by Eurocode 9 for structural uses. Therefore, based on the analysis of existing data taken from technical literature, the variation of the Young's modulus, the conventional yielding strength, the ultimate strength, the hardening factor and the material ultimate strain are represented as a function of the temperature. A mechanical model, based on the well‐known Ramberg‐Osgood formulation, which appropriately takes into account the peculiarities of such materials at high temperatures, is provided. In particular, the combined influence of the hardening factor and temperature on the material stress‐strain relationship is considered and analysed. Then, the proposed model has been introduced in a finite element program, devoted to the global analysis of structures under fire. Finally, the results obtained for a simple portal frame structure, designed with different aluminium alloys, are presented, showing the valuable effect of the material modelling on the structural behaviour of aluminium structures under fire.
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Al-Khedher, M. A., R. S. Yassar, C. Pezeshki, and D. P. Field. "A novel structural-based approach to model the age hardening behaviour of aluminium alloys." Modelling and Simulation in Materials Science and Engineering 14, no. 6 (2006): 905–21. http://dx.doi.org/10.1088/0965-0393/14/6/002.
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Khadyko, M., O. R. Myhr, S. Dumoulin, and O. S. Hopperstad. "A microstructure-based yield stress and work-hardening model for textured 6xxx aluminium alloys." Philosophical Magazine 96, no. 11 (2016): 1047–72. http://dx.doi.org/10.1080/14786435.2016.1154995.
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Mandal, P. K. "An Experimental Study on Thermal Stability of Age-Hardenable Aluminium Alloys Modified by Scandium Inoculation." Materials Science Forum 830-831 (September 2015): 387–90. http://dx.doi.org/10.4028/www.scientific.net/msf.830-831.387.
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The Al-Zn-Mg system is a familiar age-hardenable 7xxx series of aluminium alloy. Aluminium alloys are gaining wide popularity in aeronautical, automotive, and transportation industries. Scandium (Sc) has the ability to refine grain size of cast aluminium structure. It has been possible to achieve an ideal combination of strength, density, and thermal stability because of the unique age-hardening characteristics of Sc. Moreover, low solid solubility of Sc in aluminium is responsible for the improvement of the microstructure and mechanical properties when added in small amounts (≤0.6 wt.%). Further, inoculation is an effective means of grain refinement in liquid state of as-castaluminium alloys. So, density of GP zones formation and early stage of ageing effects assessment main priority in the present work. However, coherent precipitates like ScAl3are finely dispersed to provide thermal stability by increasing recrystallization temperature. Hence, the improvement in the high temperature stability of aluminium alloys (7xxx series) may be attributed to the grain boundary pinning (e.g. Zenerdrag mechanism) by the fine precipitates.In this paper, the relationship between the mechanical behavior and microstructure characteristics of Al-Zn-Mg-Sc based alloys are investigated to understand the thermal stability mechanism of grain refinement and dispersive precipitation.
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Milkereit, Benjamin, Marco J. Starink, Paul A. Rometsch, Christoph Schick, and Olaf Kessler. "Review of the Quench Sensitivity of Aluminium Alloys: Analysis of the Kinetics and Nature of Quench-Induced Precipitation." Materials 12, no. 24 (2019): 4083. http://dx.doi.org/10.3390/ma12244083.
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For aluminium alloys, precipitation strengthening is controlled by age-hardening heat treatments, including solution treatment, quenching, and ageing. In terms of technological applications, quenching is considered a critical step, because detrimental quench-induced precipitation must be avoided to exploit the full age-hardening potential of the alloy. The alloy therefore needs to be quenched faster than a critical cooling rate, but slow enough to avoid undesired distortion and residual stresses. These contrary requirements for quenching can only be aligned based on detailed knowledge of the kinetics of quench-induced precipitation. Until the beginning of the 21st century, the kinetics of relevant solid-solid phase transformations in aluminium alloys could only be estimated by ex-situ testing of different properties. Over the past ten years, significant progress has been achieved in this field of materials science, enabled by the development of highly sensitive differential scanning calorimetry (DSC) techniques. This review presents a comprehensive report on the solid-solid phase transformation kinetics in Al alloys covering precipitation and dissolution reactions during heating from different initial states, dissolution during solution annealing and to a vast extent quench-induced precipitation during continuous cooling over a dynamic cooling rate range of ten orders of magnitude. The kinetic analyses are complemented by sophisticated micro- and nano-structural analyses and continuous cooling precipitation (CCP) diagrams are derived. The measurement of enthalpies released by quench-induced precipitation as a function of the cooling rate also enables predictions of the quench sensitivities of Al alloys using physically-based models. Various alloys are compared, and general aspects of quench-induced precipitation in Al alloys are derived.
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Nguyen, Giang Dinh, Alexander M. Korsunsky, and Jonathan Belnoue. "Coupled Damage-Plasticity Modelling of Ductile Failure in an Aluminium Alloy." Applied Mechanics and Materials 784 (August 2015): 266–73. http://dx.doi.org/10.4028/www.scientific.net/amm.784.266.
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The ductile failure of metallic alloys is characterized by the long plateau of the stress-strain response during plastic deformation. In aluminium alloys this complex process is principally mediated by crystal slip associated with dislocation nucleation, motion, interaction, and locking. This results in hardening, i.e. the increase in the flow stress and progressive exhaustion of ductility, eventually leading to damage. Therefore, in the advanced stages of deformation the strength increase at the material level competes with overall stiffness and strength decrease due to effective cross-section reduction by decohesion and voiding. Capturing the complex hierarchical failure of these materials requires developing sophisticated concurrent constitutive descriptions of both plastic deformation and damage at different stages of failure. In the present study the modelling of aluminium alloy failure is accomplished using a plasticity-based model with nonlinear hardening coupled with isotropic damage in a thermodynamically consistent framework. The model developed in this way is enhanced with nonlocal regularization to deal with material instabilities issues due to softening. Emphasis is placed on the correspondence between experimental measurements of the essential work of fracture and the non-essential work of fracture, and both local and spatial sets of model parameters. This approach is the key to assuring a constitutive response consistent with experimental observations, an issue usually overlooked in nonlocal constitutive modelling. Numerical examples are used to demonstrate the features of the new approach.
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Zimmermann, Martina, Christian Stoecker, Martin Cremer, Anton Kolyshkin, and Hans Juergen Christ. "Fatigue Behavior of Precipitation Hardening Alloys in the LCF and VHCF Regime." Advanced Materials Research 891-892 (March 2014): 476–81. http://dx.doi.org/10.4028/www.scientific.net/amr.891-892.476.
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LCF/HCF strength of precipitation hardening alloys is primarily controlled by its heat treatment condition. However, for a nickel-based superalloy and a wrought aluminium alloy it will be shown, that the VHCF behavior cannot solely be explained by the precipitation morphology. Damage accumulation is dominated by microstructure related slip localization, grain morphology and microstructural flaws. In contrast to the LCF behavior, the prediction of cyclic strength in the VHCF regime requires a detailed analysis of the competing microstructural crack initiating characteristics. Hence, new fatigue life prediction models have to be developed, which consider a statistical analysis of the failure-relevant inhomogeneities. In the case of the two materials studied, VHCF behavior is dominated by isolated and inhomogeneously distributed irreversible slip accompanied by a low dislocation density. The formation of single slip bands in favorably oriented grains in Nimonic 80A results in a decrease of the VHCF strength for the peak-aged condition. The overaged condition shows better VHCF strength due to a more homogeneous distribution of slip bands, as dislocations pile up at the overaged precipitates due to the very low strain amplitudes, while in the LCF regime the Orowan mechanism results in a weaker cyclic strength compared to the peak-aged condition. Crack initiation of the aluminium alloy EN AW-6082 on the one hand depends on the size and distribution of primary intermetallic particles of the Al-Fe-type acting as local stress raiser embedded in a strong matrix in case of the peak-aged condition. In contrast, such stress peaks are less failure-relevant due to the softer solid solution depleted matrix. Hence, the heat treatment alone does not define VHCF behavior.
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VAKULENKO, Igor Alex, Sergey PLITCHENKO, Bulent KURT, Svetlana PROYDAK, and Hangardas ASKEROV. "Transformation of structure during friction stir welding." Scientific Journal of Silesian University of Technology. Series Transport 111 (June 30, 2021): 181–91. http://dx.doi.org/10.20858/sjsutst.2021.111.16.
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In comparison with low carbon steels, there is increased interest in the use of aluminium-based alloys as materials for the manufacture of welded structures rolling stock of railway transport. During friction stir welding aluminium-based alloy, against the background of the analysis structural transformations, issues of development hardening processes are considered. Under conditions of existence, a temperature gradient at zone of weld formation, shown degree approximation alloy to the conditions of superplastic flow and influence from presence particles of the second phase on grain size of matrix is estimated. Evaluation of the separate influence grain size of matrix and state of solid solution at total hardness of the weld showed dependence of their contributions on temperature of hot plastic deformation. As the temperature of plastic deformation of alloy at area of the weld increases, contribution to the total hardness from grain size increase and on state of the solid solution decreases.
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WU, LINDA, and W. GEORGE FERGUSON. "COMPUTER MODELLING OF AGE HARDENING FOR ISOTHERMALLY AGED Al-Mg-Si ALLOYS." International Journal of Modern Physics B 20, no. 25n27 (2006): 4177–82. http://dx.doi.org/10.1142/s0217979206041057.
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Computer modelling, due to it saving time and money, has been widely used in industrial simulation. The present model, which is based on the Shercliff-Ashby methodology for the ageing of aluminum alloys, can be used to predict the yield strength (or hardness) of Al - Mg - Si alloys for the artificial ageing temperature below the solvus temperature as a function of time. With suitable input data, this model can be applied to most Al - Mg - Si alloys, wrought or cast. In the present model, input data for aluminium alloys of A356, A357 and 6061 is taken from the open literature, and then the unknown constants are calibrated from these data. After calibration, the ageing curves are constructed for different isothermal ageing temperatures. Finally, experimentally ageing heat treatments at different temperatures for casting alloys of A356 were done to validate the model.
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Pratap, Singh, and Judit Kovácsb. "Comparative HAZ softening analysis of three different automotive aluminium alloys by physical simulation." Zavarivanje i zavarene konstrukcije 66, no. 1 (2021): 23–38. http://dx.doi.org/10.5937/zzk2101023p.
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The development of high strength aluminium alloy has revolutionized the automotive industry with innovative manufacturing and technological process to provide high-performance components, weight reduction and also diversified the application field and design consideration for the automotive parts that work under severe conditions, but the selection of proper production parameters is most challenging task to get excellent results. Growing industrial demand of aluminium alloys led to the development of new welding technologies, processes and studies of various parameters effects for its intended purposes. The microstructural changes lead to loss of hardening and thereby mechanical strength in the HAZ welded joint even though the base materials are heat treatable and precipitation hardened. So, our goal is to analyse HAZ softening and analyse the sub-zones as a function of the parameter. In this paper, the influence of weld heat cycle on the heat-affected zone (HAZ) is physically simulated for Tungsten Inert Gas Welding (TIG) using Gleeble 3500 thermomechanical simulator for three different automotive aluminium alloy (AA5754-H22, AA6082-T6 & AA7075-T6) plate of 1 mm thickness. In order to simulate the sub-zones of the heat-affected zone, samples were heated to four different HAZ peak temperatures (550 °C, 440 °C, 380 °C and 280 °C), two linear heat input (100 J/mm and 200 J/mm) by the application of Rykalin 2D model. A series of experiments were performed to understand the behaviour, which make it possible to measure the objective data on the basis of the obtained image of the aluminium alloys tested with heat-affected zone tests in a Gleeble 3500 physical simulator. The main objective is to achieve the weldability of three different automotive aluminium alloys and their comparison based on the welding parameters like heat input. Further, the investigation of HAZ softening and microstructure of the specimens were tested and analysed using Vicker's hardness test and optical microscope respectively. The paper focuses on HAZ softening analysis of different grades of aluminium alloys for automotive application.
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Tenkamp, Jochen, Alexander Koch, Stephan Knorre, Ulrich Krupp, Wilhelm Michels, and Frank Walther. "Influence of the microstructure on the cyclic stress-strain behaviour and fatigue life in hypo-eutectic Al-Si-Mg cast alloys." MATEC Web of Conferences 165 (2018): 15004. http://dx.doi.org/10.1051/matecconf/201816515004.
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Aluminium alloys are promising candidates for energy-and cost-efficient components in automotive and aerospace industries, due to their excellent strength-to-weight ratio and relatively low cost compared to titanium alloys. As modern cast processing and post-processing, e.g. hot isostatic pressing, result in decreased frequency and size of defects, the weakest link depends on microstructural characteristics, e.g. secondary dendrite arm spacing (SDAS), Si eutectic morphology and α-Al solid solution hardness. Hereby, fatigue investigations of the effect of the microstructure characteristics on the cyclic stress-strain behaviour as well as fatigue mechanisms in the low cycle and high cycle fatigue regime are performed. For this purpose, samples of the aluminium cast alloy EN AC-AlSi7Mg0.3 with different Si eutectic morphology and α-Al solid solution hardness were investigated. To compare the monotonic and cyclic stress-strain curves, quasistatic tensile tests and incremental step tests were performed on two microstructure conditions. The results show that the cyclic loading leads to a hardening of the material compared to monotonic loading. Based on damage parameter Woehler curves, it is possible to predict the damage progression and fatigue life for monotonic and cyclic loading in hypo-eutectic Al-Si-Mg cast alloys by one power law.
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Petroušek, Patrik, Tibor Kvačkaj, Róbert Kočiško, et al. "Evaluation of formability of thin sheets based on Al-Mg-Si for automotive industry." Acta Metallurgica Slovaca 21, no. 3 (2015): 176. http://dx.doi.org/10.12776/ams.v21i3.615.
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<p class="AMSmaintext">In this paper is evaluated workability of four rolled aluminium alloys based AIMgSi. Static tension test was used for obtained the mechanical properties, such as tensile strength, yield strength, elongation, the strain hardening exponent and coefficient of surface anisotropy. Rolled samples used for a tensile test were taken in three different directions, namely in the direction of rolling, in 45 ° and 90° direction. The result is an consideration of suitability of the material for stamping technology. For measurement of the elongation, variations in thickness and width in real-time was used method called videoextensometry. To obtain deforming maps and left side of forming limit diagrams (FLD) was applied digital correlation method (DIC).</p>
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P K Mandal. "Surface modification of Aluminium alloy (7xxx series) by multipass friction stir processing." Global Journal of Engineering and Technology Advances 6, no. 2 (2021): 008–17. http://dx.doi.org/10.30574/gjeta.2021.6.2.0127.
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Multipass friction stir processing (MP-FSP) is a solid-state surface modification technique, which was developed based on the simple principle of FSW. Aluminium plates were subjected to MP-FSP from 1 to 14 passes along the longitudinal direction with the specified process parameters such as rotational speed of 1000 rpm and travel speed of 70 mm/min and axial force of 15 kN. Subsequently, similar process parameters had followed by doublepass friction stir processing (DP-FSP) in order to help determine the effectiveness of multipass in creating high strength of aluminium alloys. Now-a-days extensive research had focused on various process parameters such as rotational speed, traverse speed, tool design on processing of aluminium alloys and proficiently enhanced material properties. This technique has considered mostly development of green technology, which is energy efficient and environment friendly technique. Experimentally proven that the Al-Zn-Mg-Sc alloys are characterized through OM, FESEM, DSC, SEM, TEM, and mechanical properties. The tensile strength and ductility of the MP-FSP specimen improved significantly to 122.48%, and 42.55% respectively, but hardness decline to 4.84% as compared to DP-FSP. This is due to not only for refinement of cast dendritic structure and eliminate segregation in the as-cast alloy, but also to the refining of grains, such as the uniform distribution of Al3Sc and hardening precipitates. To aim of this research work is to mainly focusing on MP-FSP may enhance mechanical properties better than DP-FSP and useful for macroscale applications.
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Puzio, Sabina, Jadwiga Kamińska, Michał Angrecki, and Katarzyna Major-Gabryś. "The Influence of Inorganic Binder Type on Properties of Self-Hardening Moulding Sands Intended for the Ablation Casting Process." Journal of Applied Materials Engineering 60, no. 4 (2021): 99–108. http://dx.doi.org/10.35995/jame60040008.
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The aim of the present work is to compare the properties of self-hardening moulding sands based on inorganic binders based on sodium silicate of different modules, geopolymer binders and phosphate binders and to prove they can be used in the ablation casting process. Ablation casting is a process in which, directly after pouring the liquid alloy, the mould is sprayed with water until it is completely eroded and a finished, cooled casting is obtained. The use of proecological water-dilutable binder makes it possible to recover the sand matrix after drying the suspension that remains after the process. Moulding sands were prepared on the basis of four inorganic binders available on the market. For each of the moulding sands the bending strength was tested after 1, 2, 4 and 24 h of hardening. Then, the masses with optimum bending strength were selected and subjected to gas emissivity tests. A thermal analysis of moulding sands selected for testing was also carried out in order to determine the loss of mass during annealing. The susceptibility of moulds to erosion under the influence of ablative medium was also assessed by measuring the time of mould erosion. Tests showed the possibility of using self-hardening moulding sands based on inorganic binders for the ablation casting process of aluminium-silicon alloys.
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Paraianu, Liana, and Dorel Banabic. "Characterization of the Plastic Behaviour of AA6016-T4 Aluminium Alloy." Advanced Engineering Forum 8-9 (June 2013): 293–300. http://dx.doi.org/10.4028/www.scientific.net/aef.8-9.293.
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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 0o, 45o and 90o 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.
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Pola, Annalisa, Roberto Roberti, Ermanno Bertoli, and Disman Furloni. "Design and Production of New Aluminum Thixotropic Alloys for the Manufacture of Structural Components by Semisolid Die Casting." Solid State Phenomena 116-117 (October 2006): 58–63. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.58.
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Semi-solid processing is nowadays a powerful technology for the realization of structural components; in addition to the increase in their mechanical properties, due to the globular structure instead of the dendritic one, further developments are most likely to be expected from alloy chemical composition adjustments in order to achieve higher performances compared with the industrially used A356 and A357. Aim of this research is to try to set up new aluminium alloys for semisolid foundry applications, starting from the standard Al-Si system, at the base of all known casting processes. Different chemical compositions, based on either foundry or wrought Al alloys, have been investigated by means of computational thermodynamics (Pandat®), producing quantitative data about solidus-liquidus interval, solid fraction as a function of temperature, phase diagrams i.e. potential for age hardening, etc.. Some selected alloys, fitting the needs of good castability, proper concentration of hardening elements in the alpha phase and, obviously, easy production of feedstock material have been mechanically stirred by means of an experimental apparatus designed and self-constructed in the foundry laboratory of the university; the effect of different stirring tool configurations on the semi-solid state obtainment has also been assessed. Subsequently, the manufactured alloys have been reheated and cast into a simple die, properly designed, for the production of small samples. Microstructural investigations have been done on the stirred alloy (before and after re-heating), on the as cast and the heat treated samples to evaluate the efficiency of the designed system and of the defined alloys. Experimental tests on the processed alloys have been carried out by means of an instrumented crucible in order to verify the predicted thermodynamic properties supplied by simulation study (i.e. fs-temperature curve).
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Poletti, Cecilia, Romain Bureau, Peter Loidolt, Peter Simon, Stefan Mitsche, and Mirjam Spuller. "Microstructure Evolution in a 6082 Aluminium Alloy during Thermomechanical Treatment." Materials 11, no. 8 (2018): 1319. http://dx.doi.org/10.3390/ma11081319.
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Thermomechanical treatments of age-hardenable wrought aluminium alloys provoke microstructural changes that involve the movement, arrangement, and annihilation of dislocations, the movement of boundaries, and the formation or dissolution of phases. Cold and hot compression tests are carried out using a Gleeble® 3800 machine to produce flow data as well as deformed samples for metallography. Electron backscattered diffraction and light optical microscopy were used to characterise the microstructure after plastic deformation and heat treatments. Models based on dislocation densities are developed to describe strain hardening, dynamic recovery, and static recrystallisation. The models can describe both the flow and the microstructure evolutions at deformations from room temperatures to 450 °C. The static recrystallisation and static recovery phenomena are modelled as a continuation of the deformation model. The recrystallisation model accounts also for the effect of the intermetallic particles in the movements of boundaries.
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Piccininni, Antonio, and Gianfranco Palumbo. "Design and Optimization of the Local Laser Treatment to Improve the Formability of Age Hardenable Aluminium Alloys." Materials 13, no. 7 (2020): 1576. http://dx.doi.org/10.3390/ma13071576.
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The research of innovative methodologies to improve the Aluminium alloys formability at room temperature still remains an open question: the local modification of the material properties via short-term heat treatments followed by the stamping at room temperature is reported to be an effective alternative to the forming in warm conditions. In the present work, such a methodology has been applied to the deep drawing of an age-hardenable Aluminium alloy (AA6082-T6) using an experimental/numerical approach. A preliminary extensive material characterization was aimed at investigating the material behaviour: (i) in the as-received condition (peak hardening), (ii) in the supersaturated condition (obtained by physical simulation) and (iii) after being locally solutioned via laser heating. A Finite Element based approach (Abaqus CAE, v. 6.17) was then used to design the laser treatment of the blanks to be subsequently deep drawn at room temperature: a 2D axisymmetric model of the deep drawing process was coupled with the optimization platform modeFRONTIER in order to define the radial extent of the laser heat treated area able to maximize the Limit Drawing Ratio. The experimental tests were finally conducted for validation purposes and revealed the effectiveness of the adopted approach which allowed to improve the drawability of more than 20% with respect to the as received condition (T6).
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Lamin, Fauziana, Ahmad Kamal Ariffin Ahmad Kamal Ariffin, and Intan Fadhlina Mohamed. "Finite element analysis of plasticity behaviour of aluminium alloys in high-pressure torsion compressive loading stage." International Journal of Structural Integrity 10, no. 5 (2019): 692–703. http://dx.doi.org/10.1108/ijsi-04-2019-0037.
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Purpose The purpose of this paper is to examine the plasticity behaviour of aluminium alloys in high-pressure torsion (HPT) compressive loading stage. It is a part of the strengthen lightweight material development through severe plastic deformation. Design/methodology/approach A finite element simulation of HPT compression stage by displacement control incremental loading was proposed by taking into account an unconstraint HPT configuration. The quasi-static condition was utilised, by embedding strain hardening plasticity constitutive model and considering frictional effects, to assess the plasticity behaviour of aluminium alloys, particularly AA2024 and AA6082. Findings The present investigation clearly indicates that the deviation of material flow as a result of sticking condition of µ⩾0.5, was found to be negligible. An inhomogeneous material flow along the sample radial and thickness direction was evident, producing a stress concentration at the edge of the loaded surface, indicating the anticipated region of failure. The effective plastic strain in the compression stage was also found to be significant. Based on the effective strain response, plasticity behaviour of the compressed sample was predicted. Originality/value This paper demonstrates the plasticity behaviour of the analysed aluminium alloys. Since the mechanical properties produced by the deformed material are closely related to the exerted plastic deformation, understanding the phenomenon associated with the plastic strain development is essential. The outcome of this research will assist in seizing the opportunities of improving both material properties and the HPT procedures.
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Kasirajan, G., Sathish Rengarajan, R. Ashok kumar, G. R. Raghav, V. S. Rao, and K. J. Nagarajan. "Tensile and wear behaviour of friction stir welded AA5052 and AA6101-T6 aluminium alloys: effect of welding parameters." Metallurgical Research & Technology 117, no. 4 (2020): 405. http://dx.doi.org/10.1051/metal/2020039.
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To improve the performance and effectiveness of cost, constructing lightweight structure is the important factor for automobile, naval and aerospace industries. AA5052 and AA6101-T6 aluminium alloys are widely applied in transport industries, due to their lightweight and high strength and hence, joining of these two are unavoidable. Friction stir welding is an unconventional welding method, which is developed for constructing lightweight structures. This work describes the detailed study of friction stir welded dissimilar AA5052 and AA6101-T6 alloys. AA5052 and AA6101-T6 plates are welded with rotation rates of 765–1400 rpm and offset distances at advancing side of 0–2 mm. For this purpose, four levels of welding parameters based on Taguchi L16 orthogonal array are chosen. To determine the optimum combinational levels and identify the effect of above-mentioned parameters on tensile and wear properties, Signal to Noise ratio and ANOVA respectively are used. From the results, it is observed that the combination of 1 mm offset distance at advancing side and 1400 rpm rotating speed produces better tensile and wear properties, which is due to high heat generation, sufficient flow of materials and balanced precipitation and strain hardening effects. On the other hand, the combination of 2 mm tool offset at advancing side and 765 rpm rotational rate exhibits poor properties, which is associated with low heat input, defects formation, precipitate coarsening and lesser strain hardening effects.
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Rosenschon, Martin, Sebastian Suttner, and Marion Merklein. "Validation of Kinematic Hardening Parameters from Different Stress States and Levels of Plastic Strain with the Use of the Cyclic Bending Test." Key Engineering Materials 639 (March 2015): 385–92. http://dx.doi.org/10.4028/www.scientific.net/kem.639.385.
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The recent development of new lightweight sheet metal materials, like advanced high-strength steels or aluminium alloys, in combination with an increasing component complexity provides new challenges to the numerical material modelling in the FEM based process design. An auspicious approach to improve the quality of the numerical results – most notably in springback analysis – is the modelling of the so called Bauschinger effect achieved through implementation of kinematic hardening models. Within this paper the influence of the stress state and the level of pre-strain on the numerical simulation result of the advanced high strength steel DP-K45/78+Z will be analysed. For this purpose, a parameter identification of the kinematic hardening law according to Chaboche and Rousselier is performed at different pre-strains on the basis of experimental data from tension-compression tests as well as cyclic shear tests. Finally, the identified parameters are validated in a comparison between numerical and experimental results of a cyclic bending test.
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Kabliman, Evgeniya, and Pavel Sherstnev. "Integrated Modeling of Strength Evolution in Al-Mg-Si Alloys during Hot Deformation." Materials Science Forum 765 (July 2013): 429–33. http://dx.doi.org/10.4028/www.scientific.net/msf.765.429.
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In the present work we develop a physically based model of strength evolution during hot deformation of Al-Mg-Si alloys. The goal is to predict a change of material strength taking into account the impact of microchemistry, i.e. the influence of solutes and precipitates on strengthening and softening mechanisms. The material strengthening is considered in the present work in terms of solid solution strengthening (the Labusch-Naborro model), work hardening (the advanced one-parameter Kocks model), as well as precipitation strengthening due to the stress contribution of non-deformable particles, i.e. dispersoids (the Orowan by-pass). The material softening is described by dynamic recovery through thermal activation of dislocation climb. For the precipitation kinetics the computational thermodynamics code MatCalc (Materials Calculator) was used. The model was validated by comparison with experimental data of compression tests of the 6xxx series aluminium alloys and a reasonable agreement of the simulated and measured flow stress curves was found.
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Rajkumar, K., L. Poovazhgan, P. Saravanamuthukumar, S. Javed Syed Ibrahim, and S. Santosh. "Abrasive Assisted Electrochemical Machining of Al-B4C Nanocomposite." Applied Mechanics and Materials 787 (August 2015): 523–27. http://dx.doi.org/10.4028/www.scientific.net/amm.787.523.
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Aluminium reinforced with SiC, Al2O3 and B4C etc. possesses an attractive combination of properties such as high wear resistance, high strength to weight ratio and high specific stiffness. Among the various reinforced materials used for aluminium, B4C has outperformed all others in terms of hardening effect. Particle size reduction of B4C is found to have positive impact on the material hardness. In the view of physical properties, B4C has less density than that of SiC and Al2O3, which makes it an attractive reinforcement for aluminium and its alloys for light weight applications. In this work, Al nano B4C composite prepared by ultrasonic cavitation method was machined by Abrasive assisted electrochemical machining using cylindrical copper tool electrodes with SiC abrasive medium. In this paper, attempts have been made to model and optimize process parameters in Abrasive assisted Electro-Chemical Machining of Aluminium-Boron carbide nano composite. Optimization of process parameters is based on the statistical techniques using Response Surface Methodology with four independent input parameters such as voltage, current, abrasive concentration and feed rate were used to assess the process performance in terms of material removal rate and surface finish. The obtained results were compared with abrasive assisted electro chemical machining of Aluminium-Boron carbide micro composite and the effect of particle size on the process parameters was analyzed.
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Zyazev, V. L., V. Ya Bulanov, E. A. Kirillov, and V. A. Kopysov. "Surface hardening of carbon structural steels by gas thermal spraying with melting and powder surfacing, with alloys based on the chromium‐nickel‐aluminium system." Welding International 16, no. 4 (2002): 325–27. http://dx.doi.org/10.1080/09507110209549539.
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Zhan, Li Hua, Si Ge Tan, Ming Hui Huang, and Jie Niu. "Creep Age-Forming Experiment and Springback Prediction for AA2524." Advanced Materials Research 457-458 (January 2012): 122–29. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.122.
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Creep age-forming (CAF) technology is a new forming method, which combined age hardening and creep forming processes into one. It is mainly used to manufacture wing panels. In this paper, a set of experimental device of creep age forming is developed and the influence of process parameters on the springback of artificially aged 2524 aluminium alloys (AA2524) are investigated. The law of the comprehensive effect of aging time, aging temperature, elastic pre-deformation radius and work-piece thickness, on creep aging springback and mechanical properties of AA2524 is obtained. Based on multiple regression analysis, springback prediction model of process parameters is established and further proven experiments have then been carried out. The result shows that the maximum springback deviation between the experimental results and the prediction ones is within 9.5%. The accuracy of springback prediction model is validated, which provides a theoretical basis for process parameter optimization and springback prediction of CAF.
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Moy, Charles, Massimiliano Bocciarelli, Simon P. Ringer, and Gianluca Ranzi. "A Method to Extract Materials Properties from Multilayer Material Systems." Materials Science Forum 654-656 (June 2010): 2775–78. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.2775.
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This article presents an inverse analysis method based on an instrumented indention to extract materials properties from multilayer material systems. In this case, a 12-layers system comprising of two alternate materials is considered. Each layer is 1 μm thick. The material properties selected for the layers are within the range of common commercial aluminium alloys. The yield stress and strain hardening exponent of the two layers were identified based on a power law type equation to define the stress-strain relationship. A 2D axis-symmetric indenter having 70.3 half angle was used, which is representative of a Berkovich or a Vickers indenter. The use of finite element analyses was substituted with a fast and equally accurate approach for the iterative optimization procedure. Thus, the computation time was considerably reduced. The robustness is tested using pseudo-experimental results, in terms of indentation curve and imprint on the material, with added random noises of 2.5%, 5.0%, 7.5% and 10.0%. The proposed approach provides a good estimate of the sought material properties. It is envisaged that this approach can become of assistance in the evaluation of the material properties for multilayer coatings and small devices.
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Liu, Cheng, Andrew Norman, and Menno van der Winden. "Through Process Modelling of Microchemistry in AA3103." Materials Science Forum 519-521 (July 2006): 271–76. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.271.
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One of the challenges for the Aluminium industry is to reduce the costs and lead times of the development of novel alloys. This can be achieved by applying increasingly sophisticated models to predict the microstructures and properties of novel chemistries and processing routes. At Corus RD&T, several physically based microstructure models and one process model have been developed and integrated into a Through Process Model (TPM). The TPM presented here is constructed from microstructural sub-models that predict precipitation, work-hardening, recovery and recrystallisation. Furthermore, there is a finite difference based process model that predicts the local process variables like strain, strain rate and temperature. The final sub-model translates the predicted microstructures into product properties. In this paper the integrated model has been applied to the production chain of brazing sheet (AA3103) covering all steps from homogenisation to the braze cycle as applied by the manufacturers of for instance heat exchangers. The model predictions have been verified by comparing them to the results of full-scale a plant trial. Microstructure and mechanical properties were experimentally characterized and predicted at various production steps. Due to the limited space, here, only the results of the through process modelling on microchemistry are presented. Nevertheless it can be concluded that the (fully predictive) results of the models compare well with those found experimentally which opens up the option to use such models for alloy development.
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Pavlenko, Dmytro, Yaroslav Dvirnyk, and Radoslaw Przysowa. "Advanced Materials and Technologies for Compressor Blades of Small Turbofan Engines." Aerospace 8, no. 1 (2020): 1. http://dx.doi.org/10.3390/aerospace8010001.
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Manufacturing costs, along with operational performance, are among the major factors determining the selection of the propulsion system for unmanned aerial vehicles (UAVs), especially for aerial targets and cruise missiles. In this paper, the design requirements and operating parameters of small turbofan engines for single-use and reusable UAVs are analysed to introduce alternative materials and technologies for manufacturing their compressor blades, such as sintered titanium, a new generation of aluminium alloys and titanium aluminides. To assess the influence of severe plastic deformation (SPD) on the hardening efficiency of the proposed materials, the alloys with the coarse-grained and submicrocrystalline structure were studied. Changes in the physical and mechanical properties of materials were taken into account. The thermodynamic analysis of the compressor was performed in a finite element analysis system (ANSYS) to determine the impact of gas pressure and temperature on the aerodynamic surfaces of compressor blades of all stages. Based on thermal and structural analysis, the stress and temperature maps on compressor blades and vanes were obtained, taking into account the physical and mechanical properties of advanced materials and technologies of their processing. The safety factors of the components were established based on the assessment of their stress-strength characteristics. Thanks to nomograms, the possibility of using the new materials in five compressor stages was confirmed in view of the permissible operating temperature and safety factor. The proposed alternative materials for compressor blades and vanes meet the design requirements of the turbofan at lower manufacturing costs.
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Behrens, Bernd Arno, Thomas Hagen, S. Röhr, and Kanwar Bir Sidhu. "Selective Strain Hardening of Structure Components by Action Media Based Cold Massive Forming." Advanced Materials Research 22 (August 2007): 57–65. http://dx.doi.org/10.4028/www.scientific.net/amr.22.57.
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High strength aluminium wrought alloys as well as powder metallurgical aluminium alloys are limited regarding massive formability. The formability at room temperature can be significantly affected by superimposing hydrostatic pressure. Depending on the process control, cold forming enables locally induced strain hardening effects, whereby increased hardness or hardness gradients can be regulated. Simultaneously, the necessity of mechanical post processing is reduced by a metal forming fabrication of joint and connection elements at room temperature. By splitting the component in strengthened and not strengthened regions, specially adapted property profiles can be adjusted to the application. Thus, specially load adapted components with locally optimised property profiles e.g. ductile or high strength, brittle areas can be manufactured. A defined buckling or folding of a component in case of a crash can thereby be achieved. In this project innovative tool principles for superimposed cold solid forming will be developed. They will be used to manufacture high strength and complex aluminium structure components with specific adjustment of local strain hardening. A tool technique is to be created in order to generate locally hardened areas within massive structures by metal forming. Furthermore, the task is to determine the procedures limits for superimposed cold massive forming with specifically adjusted strain hardening of aluminium alloys. For the realisation of these aims fundamental research has to be made, by which the coherences between specific process parameters and the increased formability are determined. Furthermore, the cold hardening effects are to be adjusted by cold massive forming with superimposed hydrostatic pressure and displayed with the help of FEA. In the long term, the analysis aims at the development of pressure superimposed forming that is technically utilisable as a near net shape manufacturing process for high complex aluminium structure components with selective adjustment of local properties.
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Zhang, Zheng, and Gui Yun Yan. "Study on T-Section Aluminium Beam-Columns with Web in Compression." Advanced Materials Research 250-253 (May 2011): 1786–89. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.1786.
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Parameter analysis based on finite element methods was executed to study the in-plane stability capacity of extruded T-section aluminium beam-columns with the tip of the web in bigger compression. The analysis methods considered the effects of material nonlinearity, geometrical nonlinearity, and initial imperfection. The comparisons of calculate results of three kinds of T-sections of weak hardening alloy and strong hardening alloy between GB 50429, proposed formula and numerical methods were executed. And the analytical results show that GB 50429 is safe and suitable, and the modification formula based on GB 50429 is also safe enough and more exact than the former.
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Pradeau, A., Sandrine Thuillier, and Jeong Whan Yoon. "Bending Behavior to Fracture of an Aluminium Alloy Involving Pre-Strain." Key Engineering Materials 725 (December 2016): 495–501. http://dx.doi.org/10.4028/www.scientific.net/kem.725.495.
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The work associated to this abstract is focused on the modelling of an aluminium alloy under the shape of sheet. It characterizes the mechanical behaviour up to rupture of an AA6016 alloy, taking into account the anisotropy and the hardening of the metal. The mechanical tests on which the model is based on consist of uniaxial tension, simple shear and hydraulic bulging performed at room temperature up to rupture, except for the simple shear. The numerical model is constituted of three parts. The choice of the model is suited for ductile fracture and allows for high flexibility, thanks to a total of 21 material parameters. The material parameter identification is realised through an inverse methodology. The objective of such an approach is to minimize iteratively the gap between the experimental and numerical outputs. Validation of the results is then done with the help of bending tests. The bending tests are performed with and without pre-strain in tension prior to the air-bending. Different amplitudes of pre-strain allows to reach rupture or not in bending, thus giving the possibility to find the value of the parameter controlling the non-linear accumulation of the damage. The correlation between experiments and simulations is proved to be successful and gives a very good representation of the mechanical behaviour of the aluminium alloy studied.
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Bashkov, Oleg, Roman Romashko, Sergey V. Panin, and Tatiana Bashkova. "Acoustic Emission at the Kinetic and Development of the Structural Defects under Deformation of Aluminum Alloy." Advanced Materials Research 1091 (February 2015): 119–24. http://dx.doi.org/10.4028/www.scientific.net/amr.1091.119.
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The paper presents the results of studies the deformation behavior of aluminium alloy D16 by acoustic emission (AE) method. The purpose of this study was to establish the deformation stages and deformation mechanisms at each stage. Studies were carried out on the samples of aluminum alloy D16 (analog 7075). This paper contains a method for the separation of AE signals. The method of AE sources identification based on the the two-parameter distribution analysis (frequency parameter Kfvs energy of AE signals). The frequency parameter Kf is based on wavelet transform of AE signals. Two-parameter distribution allows one to separate the AE signals emitted by dislocations from the signals of micro cracks. The investigation results allowed the various deformation stages to establish by the different types of AE signals. By the AE analysis shows the dislocation mechanism of hardening the aluminum alloyD16. The paper presents the results that characterize the influences of heat treatment and structural condition of aluminum alloy on the AE parameters.
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Makaruk, А. A., О. V. Samoylenko, Yu N. Ivanov, N. S. Chashchin, and N. V. Minaev. "Methodology for calculating the technological parameters of preventive deformation of the hardened parts of the "wall" type." Proceedings of Irkutsk State Technical University 25, no. 1 (2021): 8–16. http://dx.doi.org/10.21285/1814-3520-2021-1-8-16.
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The article aims to establish the effect of preventive deformation on the accuracy of aircraft parts made from the thermally hardened aluminium alloy 1933T2, after blasting hardening. Determination of the impact of preventive deformation was carried out by analysing structural parts of the "wall" type produced using various technological sequences. Sample 1 was produced using a standard manufacturing sequence: milling – blasting hardening – blasting correction. Sample 2 was produced as follows: milling – preventive deformation – hardening – blasting correction. The deformation of the samples was determined at checkpoints by deviations from flatness based on bending deflections. In sample 2, preventive deformation was performed on its ridges by a rolling device. The calculation of the technological parameters of the rolling device was conducted following the principle of superposition of individual operations, such as rolling and blasting hardening. The definition of the parameters of preventive deformation of sample 2 was based on the results ob tained for sample 1. It was established that, for both samples, the deviation from flatness after milling comprised 2.5 mm. The maximum deviation of sample 1 (without preventive deformation) after blasting hardening was 2.6 mm under a high degree of surface saturation. The maximum deviation of sample 2 (with preventive deformation) after blasting hardening did not exceed 0.4 mm, which corresponds to the acceptable deviation of such structural parts. Thus, the inclusion of the preventive deformation stage in the manufacturing process, with consideration of the deviations resulting from the milling stage, allows minimisation of deviations from the required form after blasting hardening. An analysis of the obtained re[1]sults confirmed that preventive deformation of structural parts reduces distortions after blasting hardening. Therefore, it is advisable to use the following manufacturing sequence: preventive deformation → hardening by a blasting method → correction by a blasting method.
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Castaldo, Paolo, Elide Nastri, and Vincenzo Piluso. "Evaluation of Rotation Capacity of RHS Aluminium Alloy Beams by FEM Simulation: Temper T4." Key Engineering Materials 710 (September 2016): 288–94. http://dx.doi.org/10.4028/www.scientific.net/kem.710.288.
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The aim of this work consists in the numerical assessment of the moment-rotation behaviour of RHS aluminium alloy beams subjected to non-uniform bending through an extensive parametric analysis performed by means of FE code ABAQUS investigating the influence of the main geometrical and mechanical parameters. In particular, the influence of the flange slenderness, web stiffness and moment gradient are investigated by adopting the constitutive law proposed by Eurocode 9 based on the Ramberg-Osgood model whose shape factor characterise the hardening behaviour of the material. The investigations concern these factors considered separately as well as their interaction. The results are herein reported with reference to temper T4 and show the importance of some of the investigated parameters on both buckling strength and rotation capacity of aluminium alloy beams.
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Fribourg, G., Y. Bréchet, A. Deschamps, and A. Simar. "Microstructure-based modelling of isotropic and kinematic strain hardening in a precipitation-hardened aluminium alloy." Acta Materialia 59, no. 9 (2011): 3621–35. http://dx.doi.org/10.1016/j.actamat.2011.02.035.
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Sawicki, Sylwester, Anna Kawałek, Konrad Laber, et al. "Plastometric Testing of Rheological Properties of 5083 and 5754 Aluminium Alloy." Key Engineering Materials 682 (February 2016): 362–66. http://dx.doi.org/10.4028/www.scientific.net/kem.682.362.
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The paper present a method for determining the real steel work-hardening curves based on the cylindrical specimen compression test. The subject of testing were 5083 and 5754 aluminium alloy. The tests were carried out using the physical simulator of metallurgical processes GLEEBLE 3800 (Figure 1a) for the temperature range of 400 ÷ 560 °C and the strain rate range of 0,1 - 1,0s-1. Based on plastic deformation parameters recorded during the experiment, mathematical processing, that is the digital filtration and approximation of the obtained testing results, will be performed. Then, using the inverse method, the actual values of the coefficients of the numerical models for the rheological properties of the tested materials will be determined.
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Castaldo, Paolo, Elide Nastri, and Vincenzo Piluso. "Proposal for an Empirical Evaluation of Rotation Capacity of RHS Aluminium Alloy Beams Based on FEM Simulations." Key Engineering Materials 710 (September 2016): 231–37. http://dx.doi.org/10.4028/www.scientific.net/kem.710.231.
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The aim of this work is the development of an empirical relationship for evaluating the rotation capacity of RHS aluminium alloy beams, for temper T4 and T6. The proposed relationships are based on the numerical results coming from an extensive parametric analysis performed by means of FE code ABAQUS for different materials, which gain insight into the influence of all the geometrical and mechanical parameters affecting the ultimate behaviour. In particular, the influence of the materials strain hardening, flange slenderness, web stiffness, shape factor and moment gradient the on the plastic behaviour of such beams has been investigated. Successively, by means of monovariate and multivariate non linear regression analyses, empirical relationships are provided in order to predict the rotation capacity of RHS aluminium alloy beams starting from their geometrical and mechanical properties. This paper is focused on this issue.
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Hopperstad, Odd Sture, Ida Westermann, Ketill Olav Pedersen, Trond Furu, and Tore Børvik. "Influence of Processing Route on the Work-Hardening and Ductile Fracture of an AA6060 Aluminium Alloy." Materials Science Forum 794-796 (June 2014): 284–89. http://dx.doi.org/10.4028/www.scientific.net/msf.794-796.284.
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Tensile tests on smooth and notched axisymmetric specimens were carried out to determine the large strain work-hardening curves and the ductile fracture characteristics of an AA6060 aluminium alloy for three different processing routes. The alloy was processed in three subsequent steps: 1) casting and homogenization, 2) extrusion, and 3) cold rolling and heat treatment to obtain a recrystallized grain structure. After each processing step, the material was tested after natural ageing for more than one week. A laser-based extensometer was used to continuously measure the average true strains to failure in the minimum cross-section of the specimens and the true stress-strain curves were calculated. Since these curves are influenced by necking, they do not represent the correct work-hardening of the material. Accordingly, finite element (FE) simulations of the tensile tests on the smooth axisymmetric specimens were conducted to determine the work-hardening curves to failure, using an optimization tool that interfaced with the nonlinear FE code and the experimental stress-strain curves as objectives. The microstructure of the alloy was characterized after the three processing steps by optical and scanning electron microscopy, and fractography was used to investigate the failure mechanisms.
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Castaldo, Paolo, Elide Nastri, and Vincenzo Piluso. "Evaluation of Rotation Capacity of RHS Aluminium Alloy Beams by FEM Simulation: Temper T6." Key Engineering Materials 710 (September 2016): 281–87. http://dx.doi.org/10.4028/www.scientific.net/kem.710.281.
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The aim of this work is the numerical assessment of the ultimate behaviour of aluminium alloy beams subjected to non-uniform bending. An extensive numerical analysis has been performed by means of FE code ABAQUS with reference to RHS sections considering different values of the main geometrical and mechanical parameters. In particular, regarding the geometrical parameters the flange slenderness, the flange-to-web slenderness ratio and the moment gradient parameter have been considered. In particular, their influence on the ultimate behaviour of such beams has been investigated by adopting the material constitutive law proposed by Eurocode 9 based on the Ramberg-Osgood model. The investigations concern these parameters considered separately as well as their interaction. The results are herein reported with reference to temper T6 and show the importance of the investigated parameters on the buckling strength and the rotational capacity of aluminium alloy beams. Temper T6 gives rise to a quite low hardening compared to temper T4, which is analysed in a companion paper.
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Krumphals, Friedrich, Pavel Sherstnev, Stefan Mitsche, S. Randjelovic, and Christof Sommitsch. "Physically Based Microstructure Modelling of AA6082 during Hot Extrusion." Key Engineering Materials 424 (December 2009): 27–34. http://dx.doi.org/10.4028/www.scientific.net/kem.424.27.
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Process parameters in aluminium extrusion technology are key points that influence product properties. The precipitation hardening aluminium alloy 6082 is investigated according to different process conditions and the influence onto the final microstructure is simulated as well as experimentally verified. A physical microstructure model based on three dislocation types and three nucleation sites for recrystallization is implemented into the commercial Finite Element package FORGE 2008 to calculate both the microstructure evolution during the extrusion process as well as the recrystallized fraction after the process. The precipitation kinetics during homogenization was investigated using the thermodynamic calculation software MatCalc since the main nucleation mechanism for recrystallization is particle stimulated. The experimental validation was done by miniature extrusion tests and the microstructure was investigated metallographically and by EBSD measurements.
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Bernstock-Kopaczyńska, E., and Magdalena Jabłońska. "Determination of Thermal Diffusivity and Influence of Defect Structure in Alloys Based on the Fe-Al System." Defect and Diffusion Forum 336 (March 2013): 129–34. http://dx.doi.org/10.4028/www.scientific.net/ddf.336.129.
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Alloys of the Fe-Al system are interesting due to occurrence of long-range order and many thermal vacancies at high temperature, which lead to not only significant hardening, but also cause changes of physical properties. High temperature diffusion is conditioned by structural defects in solids, such as vacancies, foreign atoms and dislocations influencing thermal characteristics of a solid solution, among others the thermal diffusivity coefficient. Measurement of thermal diffusivity was performed at room temperature using the laser flash method. For characterization of the defect structure, positron annihilation lifetime spectroscopy was used. The data were presented for alloys with 28 and 38 at.% aluminium without chromium and containing 5 at. % Cr addition. The results showed that thermal diffusivity decreased with aluminium content and deviation from stoichiometry. In the studies, different structural defects in the alloys were observed.
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Gottstein, Günter, Mischa Crumbach, L. Neumann, and R. Kopp. "Through-Process Texture Simulation for Aluminium Sheet Fabrication." Materials Science Forum 519-521 (July 2006): 93–102. http://dx.doi.org/10.4028/www.scientific.net/msf.519-521.93.
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We introduce a simulation procedure for through-process texture and anisotropy prediction, in particular for AA5182 sheet production from hot rolling through cold rolling and annealing. The FEM package ‘T-Pack’ based on the software LARSTRAN served as a process model. It was combined with physics based microstructure models for deformation texture (GIA), work hardening (3IVM), nucleation texture (ReNuc), and recrystallization texture (StaRT). The terminal sheet texture was used for a FEM simulation of cup drawing. A new concept of interactively updated texture based yield locus predictions was employed. The simulation predictions were compared to experimental data. The procedure can be applied to a wide variety of Aluminum alloys.
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di Michele, Gabriella, Pasquale Guglielmi, Gianfranco Palumbo, and Donato Sorgente. "Investigation on the Strain Behaviour of a Precipitation-Hardenable Aluminium Alloy through a Temperature Gradient Based Heat Treatment." Key Engineering Materials 639 (March 2015): 361–68. http://dx.doi.org/10.4028/www.scientific.net/kem.639.361.
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In this work the strain behaviour of the heat-treated 6xxx series aluminium alloy AC170PX is investigated by a not conventional approach. Thanks to the low density combined with good mechanical properties, this aluminium alloy is often adopted for automotive applications. Despite these advantages, its formability at room temperature is low. In order to overcome this limit, a distribution of the material properties can be achieved by a local heat treatment (Tailored Heat Treated Blanks). In this context, to evaluate the effects of those parameters mainly affecting the precipitation hardening (aging temperature and aging time), a first experimental campaign was conducted using conventional furnace heat treatment in different conditions . Tensile tests were run with the aim of determining the flow and the aging curves of the heat treated specimens. Starting from these results, a not uniform heat treatment was designed using a Gleeble physical simulator Heat treatments based on a temperature gradient along the sample were performed. Then, tensile tests of the so heated specimens were carried out at room temperature. Through a digital image correlation system both the distribution and the evolution of the strain along the gauge length of the specimen were analysed in order to obtain the hardening/softening working conditions related to a specific heating cycle. These results were validated by the comparison with the data obtained from the first experimental campaign.