Microstructure and mechanical properties of an Mg-3Zn- o.5Zr-5HA nanocomposite processed by ECAE

Mg matrix composites reinforced by natural bone constituent hydroxyapatite (HA) particles have shown promising in-vitro corrosion resistance but are inconsistent in both electrochemical and mechanical performances because of severe particle segregations. The present work was carried out to investigate the feasibility of a novel technology that combines high shear solidification and equal channel angular extrusion (ECAE) for fabricating Mg-HA nanocomposites. Experiments showed that the high shear solidification resulted in a fine and uniform grain structure with a globally uniform HA nanoparticles in fine clusters and the ECAE processing of the as-cast composites resulted in further grain refinement and more importantly the breakdown of nanoparticle aggregates, leading to the formation of a dispersion of true nanoparticles in the Mg alloy matrix with improved mechanical properties. This paper describes mainly the microstructural features and mechanical performance of Mg-3Zn-0.5Zr-xHA (x 1, 3, 5, 10) nanocomposites, in which the HA was in spherical shape with an average diameter of ∼20nm © Published under licence by IOP Publishing Ltd

Finite element study of deformation behaviour of Al- 6063 alloy developed by equal channel angular extrusion

The objective of this work is to evaluate the equivalent plastic strain levels induced by equal channel angular extrusion (ECAE) in an annealed Al-6063 alloy after six passes at a temperature of 200°C following route A with a constant ram speed of 30 mm/min through a die angle of 90° between the die channels using the finite element method (FEM). ECAE process is simulated using the DEFORM-3D software through a three-dimensional analysis. Grain refinement is simulated by forcing the element size to zero. It is found that for a very fine mesh the PEEQ converges to 1.046

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

Obtención de microestructuras de grano ultrafino en aleaciones de aluminio mediante extrusión en canal angular (ECAE)

Al 5083 samples have been subjected to 90º equal-channel angular extrusion (ECAE) at 270ºC. After ECAE, the microhardness was measured and the texture for the plane perpendicular to the extrusion direction was analysed by X-Rays and EBSD. The microstructure was characterized by optical microscopy and EBSD. As deformation accumulates the hardness increases until it reaches saturation at an effective strain of about ε∼4. With regard to the texture, it has been shown that a high density of {111} planes are oriented parallel to the shear plane of the last pass.<br><br>Varias muestras de aluminio 5083 se han sometido a extrusiones en canal angular de 90º a 270ºC. A continuación se midieron las durezas de las muestras obtenidas y se caracterizó la textura en el plano perpendicular a la dirección de extrusión mediante Rayos-X y difracción de electrones retrodispersados (EBSD). La caracterización microestructural se hizo mediante microscopio óptico y EBSD. Se ha observado que la dureza aumenta sensiblemente con el grado de deformación y que alcanza un nivel máximo de saturación a partir de ε∼4. En cuanto a la textura, se observa que los planos {111} tienden a orientarse paralelos al plano de la última cortadura

Correcting tensile test results of ECAE-deformed aluminium

Performing tensile tests on ECAE material reveals a long post-uniform elongation. In order to calculate correct true stress–true strain diagrams, three different approaches are used: measurements of the actual sample geometry, a neck evolution model proposed by Segal [V.M. Segal, S Ferrasse, F. Alford, Mater. Sci. Eng. A442 (2006) 321–326] and an inverse modelling method by finite element (FE) simulations

Recent progress on the study of the microstructure and mechanical properties of ECAE copper

Results on the microstructure and the tensile properties of equal channel angular extruded (ECAE) copper processed for one to 16 passes are presented and compared with the available literature data. With increasing number of passes (N), the microstructure changes from a strongly elongated shear band structure after N=1 and 2, towards a more equiaxed subgrain and grain structure. This is accompanied by a decrease in the cell wall or subgrain-boundary widths and an increase in recovered or even recrystallised grain structures with low dislocation densities. Electron backscatter diffraction measurements have indicated that for lower N, the location of Σ3 boundaries is restricted to shear bands, while at greater N, Σ3 boundaries were found to be more widely distributed. Texture measurements indicate close similarity with simple shear texture components and a spread of the orientation components with greater N. Upon comparing the tensile behaviour of as-ECAE Cu with the surveyed literature, broad agreement on the strength of the material is achieved. However, a strong variation in the percentage elongation to failure is also noted. Strain hardening and deformation kinetic analysis via strain rate jump tests indicate an evolution from stage III to V hardening during post-ECAE compression and a saturation in the strain rate sensitivity after N=4 resulting in maximum values of ∼0.02. Our results suggest that rather than a change in deformation mechanism, the increase in ductility with increasing N is associated with an increase in the mean free path of dislocations—with the grain boundaries remaining actively involved as the transmitter of plastic strain and their interaction with dislocations being the rate controlling deformation mechanis

Modelling of ecae process of Al-Cu bimetallic charge

In the work the analysis of stress intensity and normal stresses existing into the round bimetal rod extruded through the angle channel were analysed. The aim of the research was an assessment of usability ECAE process to joining bimetal layers. FEM modelling was verified by laboratory tests