Effect of frictional boundary conditions and percentage area reduction on the extrusion pressure of Aluminum AA6063 alloy using FE analysis modelling

© 2020 by the authors; licensee Growing Science, Canada. This is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).Finite Element Analysis was carried out to describe the effect of frictional boundary conditions and percentage reduction on deformation modelling (forward extrusion) of Aluminum AA6063 alloy. Curved die profiles of regular polygons (square, hexagonal, heptagonal, and octagonal) were designed using MATLAB R2009b and Autodesk Inventor 2013 to generate the coordinate and thesolid CAD model of the die profile respectively form a circular billet. The numerical analysis was performed using DeformTM-3D commercial package with frictional boundary conditions of 0.38 and 0.75 representing the wet and dry condition and varying the percentage reduction of 50%, 70%, and 90%. The results of the temperature distribution, effective stress, effective strain, andstrain rate were reported. As the percentage area reduction increases, the extrusion pressure also increases with an increasing frictional condition, and die length. Also, extrusion pressure decreases when the side of the polygon increases from square-shaped section follow by hexagonal shaped-section and least in octagonal shaped-section for both friction factors and percentage areareductions. For a given percentage reduction and cross-sectional area, there is no distinct difference between the predictive loads for the shaped-polygons. When the result of this analysis is compared with the experimental results from the literature, it is evident that DeformTM-3D is an effective tool for finite element analysis of non-isothermal deformation processes.Peer reviewedFinal Published versio

Experimental and numerical prediction of extrusion load at different lubricating conditions of aluminium 6063 alloy in backward cup extrusion

In the present research work using a backward cup extrusion (BCE) die profile, different lubricating conditions on aluminum alloy AA6063 have been experimentally and numerically investigated to predict the extrusion load. It was obvious that due to an increase in applications of the extrusion process, many researchers have worked on the extrusion process using different methods to achieve their aims. This experiment was conducted with three different lubricants namely: Castor oil, Palm Oil and tropical coconut oil; as well as without lubricants. Different lubricating conditions were employed of varying strain rates ranges from 1.5×10-3s-1, 2.0×10-3s-1, 2.5×10-3s-1, and 3.0×10-3s-1; Numerical analysis and simulation for dry and lubricated conditions during extrusion load were also performed using DEFORM 3D software. The results show that prediction extrusion load increases with increasing strain rates. The maximum extrusion load was found to be higher for extrusion without lubricants. In all cases of strain rate, palm oil showed a lower extrusion load compared to the other lubricants. Castor oil indicated the highest extrusion load when the experiment was carried out using lubrication. There was a consistent agreement between the result gotten from the experiment and simulation results of the extrusion load-strike curve.Peer reviewedFinal Published versio

Extrusion limits of magnesium alloys

Magnesium alloys are generally found to be slower to extrude than aluminum alloys; however, limited quantitative comparisons of the actual operating windows have been published. In this work, the extrusion limits are determined for a series of commercial magnesium alloys (M1, ZM21, AZ31, AZ61, and ZK60). These are compared with the limits established for aluminum alloy AA6063. The maximum extrusion speed of alloy M1 is shown to be similar to AA6063. Alloys ZM21, AZ31, ZK60, and AZ61 exhibit maximum extrusion speeds 44, 18, 4, and 3 pct, respectively, of the maximum measured for AA6063. For AZ31, the maximum extrusion speed is increased by 22 pct after homogenization and by 64 pct for repeat extrusions. The variation in the extrusion limits with changing alloy content is rationalized in terms of differences in the hot working flow stress and solidus temperature.<br /

As-Cast Residual Stresses in an Aluminum Alloy AA6063 Billet: Neutron Diffraction Measurements and Finite Element Modeling

The presence of thermally induced residual stresses, created during the industrial direct chill (DC) casting process of aluminum alloys, can cause both significant safety concerns and the formation of defects during downstream processing. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. Recently, the variation in residual elastic strains in the steady-state regime of casting has been measured as a function of radial position using neutron diffraction (ND) in an AA6063 grain-refined cylindrical billet. In the present study, these measurements are used to show that a well-designed thermomechanical finite element (FE) process model can reproduce relatively well the experimental results. A sensitivity analysis is then carried out to determine the relative effect of the various mechanical parameters when computing the as-cast residual stresses in a cylindrical billet. Two model parameters have been investigated: the temperature when the alloy starts to thermally contract and the plasticity behavior. It is shown that the mechanical properties at low temperatures have a much larger influence on the residual stresses than those at high temperature

Mechanical characterization and constitutive parameter identification of anisotropic tubular materials for hydroforming applications

This paper aims to identify the constitutive parameters of anisotropic tubular materials and to verify the accuracy of models' prediction. The identification of the constitutive parameters is based on information obtained from tensile tests, performed on samples cut from the tubes, and from the free tubular bulge test, using a home-developed bulge forming machine. Two tubular materials exhibiting different anisotropic behaviour and work hardening characteristics are investigated: a mild steel S235 seamed tube and an aluminium alloy AA6063 extruded tube. It is shown that advanced phenomenological yield functions, including a large number of anisotropy parameters, can accurately describe the plastic flow of highly anisotropic tubular materials during the tube hydroforming process. However, parameter identification procedure of advanced yield criteria requires a high number of experimental tests. Thus, in order to enable the parameter identification of these yield criteria when using a reduced set of experimental results, the present study develops a method that combines tensile tests with (i) a free bulge test, which is used to characterize the biaxial stress state experienced by the tube during the bulge testing, and (ii) some generated artificial input data. Finally, the proposed method shows an excellent agreement between numerical predictions and experimental results.The authors gratefully acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) via the projects PTDC/EMS-TEC/1805/2012 and PEst-C/EME/UI0285/2013 and by FEDER funds through the program COMPETE – Programa Operacional Factores de Competitividade, under the project CENTRO-07-0224-FEDER-002001 (MT4MOBI). The first author is also grateful for the Post-Doc grant.info:eu-repo/semantics/publishedVersio

Anti-Corrosion and Passivation Potential of AA6063-Type Al-Mg-Si Alloy with Avogadro Natural Oil in HCl Solution

The electrochemical study of the passivation potential of AA6063-type Al-Mg-Si alloy in Avogadro Natural Oil/HCl Interface was studied using weight loss and potentiodynamic techniques. The result shows that the corrosion rate increases with an increase in exposure time but decrease as the concentration of inhibitor increases. The result of both weight loss and potentiodynamic show good agreement as can been seen that the inhibition efficiencies was found to increase as concentration of inhibitor increases. Equally the additive helps to retard the rate of corrosion and increase the polarization resistance thereby lowering the corrosion density of the system. The presence of the additive was also seen to affect both the cathodic and anodic half which shows that the inhibitor acts as a mixed-type inhibitor. The surface morphology of as-corroded samples assessed with scanning electron microscopy show that the attack was severely reduce in the presence of the Avogadro natural oil

Measuring the Deformation of a Flat Die by Applying a Laser Beam on a Reflecting Surface

The design of extrusion dies depends on the experience of the designer. After the die has been manufactured, it is tested during an extrusion process and machined several times until it works properly. The die is designed by a trial and error method which is expensive interms of time consumption and the amount of scrap. Research is going on to replace the trial pressing with finite element simulations that concentrate on material and tool analysis. In order to validate the tool simulations, an experiment is required for measuring the deformation of the die. Measuring the deformation of the die is faced with two main obstacles: high temperature and little free space. To overcome these obstacles a method is tried, which works by applying a laser beam on a reflecting surface. This cheap method is simple, robust and gives good results. This paper describes measuring the deformation of a flat die used to extrude a single U shape profile. In addition, finite element calculation of the die is performed. Finally, a comparison is performed between experimental and numerical results

Structural Modification, Strengthening Mechanism and Electrochemical Assessment of the Enhanced Conditioned AA6063-type Al-Mg-Si Alloy

Enhancement of engineering materials is essential for averting service failure and corrosion attack in the industries. The impact of Ni as inoculant and solidification process on the corrosion resistance of an Al-Mg-Si alloy has been investigated in 3.65% NaCl solution using potentiodynamic polarization measurement. The alloying compositions and phase change were determined with energy dispersive spectroscopy (EDX) and x-ray diffraction (XRD). The surface morphology of the alloyed sample using scanning electron microscope (SEM) showed that Ni particles were well dispatched along the interface. The addition of Ni to Al-Mg-Si alloy led to the precipitation and crystallization of Al2Ni and AlNi2 formed at the grain boundaries. Equally, as the percentage of Ni content increases in the alloy, the corrosion rate decreased due to the presence of Al2Ni3 which proceeded at active regions. Inoculation of Ni particles coupled with increase in solidification reduces the possibility of corrosion penetration within the structural interfac

STUDY OF THE ELECTROCHEMICAL BEHAVIOR AND SURFACE INTERACTION OF AA6063 TYPE AL-MG-SI ALLOY BY SODIUM MOLYBDATE IN SIMULATED SEA WATER ENVIRONMENT

The potential of sodium molybdate on the corrosion of aluminium alloy AA6063 type was examined with the view to study the electrochemical and surface degradation for metal-inhibitor interface using gravimetric and electrochemical corrosion techniques in simulated s~awater environment. The microstructures of as-corroded samples were also assessed for their surface morphology.The results show thatcorrosion rate decreased with an increase in the inhibitor concentration and exposure time. Equally, the inhibition efticiency increased with inhibitor addition with maximum efficiency obtained at 5g/v sodium molybdate addition. The adsorption of the molecules of the extract on the aluminium alloy surface obeyed the Langmuir adsorption isotherm. The potentiodynamic polarization results showed that sodium molybdate acted as mixed-type i•1hibitor