scholarly journals Electromagnetic Stirring versus ECAP: Morphological Comparison of Al-Si-Cu Alloys to Make the Microstructural Refinement for Use in SSM Processing

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Luis Vanderlei Torres ◽  
Luis Fernando Torres ◽  
Eugênio José Zoqui
Keyword(s):  
Equal Channel Angular Pressing ◽  
Morphological Evolution ◽  
Direct Chill ◽  
Solid Particles ◽  
Electromagnetic Stirring ◽  
Semisolid State ◽  
Morphological Comparison ◽  
Globular Structure ◽  
Cross Sectional ◽  
Angular Pressing

This work evaluates the morphological evolution at the semisolid state of the Al-4.0wt%Si-2.5wt%Cu alloy produced by direct chill casting under electromagnetic stirring (EMS) and by one equal channel angular pressing (ECAP) pass. The ECAP emerged as a promising technique capable of reduction and homogeneous metals microstructure imposing large deformations occurs in a matrix that contains two channels of the same cross-sectional area and forms an angle of 120°. The materials were submitted to reheating treatment in condition of 60% solid fraction at treatment times of 0, 30, and 90 s. Comparing the two cases, we have the presented ECAP process that had an excellent response to the recovery and recrystallization mechanisms, and refined microstructures ideal for thixoforming were produced. Primary particle sizes of about 45 μm and grain sizes of about 75 μm and a circularity shape factor of more than 0.60 were obtained. The low silicon alloy, Al-4.0wt%Si-2.5wt%Cu, presented excellent refinement when processed via equal channel angular pressing, presenting good morphological stability at the semisolid state, without significant changes in size or shape of the solid particles. This fully globular structure is favourable for thixoforming processes.

Comparison of Morphological Evolution of Al-7wt%Si-2.5wt%Cu Alloy Produced by Direct Chill Casting/Electromagnetic Stirring and ECAP

2016 ◽  
Vol 256 ◽  
pp. 17-24 ◽  
Author(s):  
Luis Vanderlei Torres ◽  
Cecilia Tereza W. Proni ◽  
Eugênio José Zoqui
Keyword(s):  
Liquid Fraction ◽  
Morphological Evolution ◽  
Metal Flow ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Electromagnetic Stirring ◽  
Semisolid State ◽  
Grain Refiner ◽  
Chill Casting ◽  
Cu Alloy

In semisolid state forming the thermodynamic control of the solid liquid transition is necessary but not sufficient condition for having a good processing. For thixoforming it is critical to have a refined microstructure that during the heating to the semisolid state, achieve a mixture of small spheres immerse in liquid, which is crucial in order to get the best rheological properties for the slurry. This work compares the morphological evolution at the semisolid state of the Al-7wt%Si-2.5wt%Cu alloy produced by a) direct chill casting under electromagnetic stirring (EMS) combined with grain refinement and b) processed via one single pass in an equal channel angular pressing. EMS introduces metal flow during solidification that allows the better distribution of the nuclei provide by the grain refiner. ECAP has emerged as a promising technique capable of imposing large homogeneous deformations in metals, that could leads to a optimal grain refining. The ECAP deformation occurs in a die that contains two channels of the same cross-sectional area and form an angle of 120°. The raw materials were submitted to a heating treatment in order to reach 60% liquid fraction, at soaking times of 0s, 30s, 90s and 210s and the microstructure was evaluated via B&W and color metalography. Comparing the two production processes, it is observed that the ECAP process is highly efficient: while the traditional EMS method produced grains about 150 μm size, ECAP technique achieved grains of 60 μm, providing a fully globular structure, which exhibit favorable characteristics for the thixoforming process reaching to apparent viscosity about 2*104Pa.s.

A Novel Process for Fabrication of Globular Structure by Equal Channel Angular Pressing and Isothermal Treatment of Semisolid Metal

2008 ◽  
Vol 141-143 ◽  
pp. 445-450 ◽  
Author(s):  
H. Meidani ◽  
S. Hossein Nedjad ◽  
Mahmoud Nili-Ahmadabadi
Keyword(s):  
Equal Channel Angular Pressing ◽  
Microstructural Evolution ◽  
Microstructure Evolution ◽  
Isothermal Treatment ◽  
Semisolid State ◽  
Isothermal Heating ◽  
Globular Structure ◽  
Globular Microstructure ◽  
Angular Pressing ◽  
New Process

A new process for fabrication of semisolid billets is introduced, which involves equal channel angular pressing and isothermal heating in the semisolid state. The process leads to a relatively fine globular microstructure. The microstructure evolution during isothermal treatment is studied and it is shown that dendrites breaking up has happened during equal channel angular pressing in semisolid state. The microstructural evolution during isothermal heating and the mechanism for the formation of the globular structure is tried to be understood and also modeled.

Morphological Evolution of Al-2wt%Si-2.5wt%Cu Alloy Produced by EMS and EMS Enhanced by ECAP

2014 ◽  
Vol 217-218 ◽  
pp. 105-110 ◽  
Author(s):  
Luis Vanderlei Torres ◽  
Davi Munhoz Benati ◽  
Eugênio José Zoqui
Keyword(s):  
Raw Materials ◽  
Morphological Evolution ◽  
Production Method ◽  
Direct Chill ◽  
Raw Material ◽  
Cross Sectional ◽  
Angular Pressing ◽  
Cu Alloy ◽  
Heating Treatment ◽  
Second Procedure

This work evaluates the morphological evolution at the semisolid state of the Al-2wt%Si-2.5wt%Cu alloy produced by direct chill casting under electromagnetic stirring (EMS) and this same raw material enhanced by one equal channel angular pressing pass (ECAP), specially designed to produce raw material for thixoforming processes. The traditional EMS production method is compared to ECAP in order to determine if a second procedure is necessary for this particular alloy. The ECAP process emerged as a promising technique capable of imposing severe homogeneous deformation in metals, which could improve thixoforming processes. The ECAP deformation occurs in a matrix that contains two channels of the same cross-sectional area and form an angle of Φ = 90° and Φ = 120°, the process can be repeated many times allowing to control the microstructure and properties of the materials. Both raw materials, EMS and EMS + ECAP were submitted to re-heating treatment in two conditions of solid fractions, 45% and 60% at soaking times of 0s, 30s and 90s. With this procedure primary particle sizes of about 60 μm were obtained, which exhibit favourable characteristics for the thixoforming process.

The Effect of Equal Channel Angular Pressing on Coarsening Kinetics of AZ80–0.2Y–0.15Ca Alloy in Semisolid State

2020 ◽  
Vol 22 (12) ◽  
pp. 2000415
Author(s):  
Lingling Fan ◽  
Mingyang Zhou ◽  
Lingbao Ren ◽  
Houyi Li ◽  
Hongtao Zhang ◽  
...  
Keyword(s):  
Equal Channel Angular Pressing ◽  
Semisolid State ◽  
Angular Pressing ◽  
Coarsening Kinetics ◽  
Kinetics Of

scholarly journals Numerical Investigation of Plastic Strain Homogeneity during Equal-Channel Angular Pressing of a Cu-Zr Alloy

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1505
Author(s):  
Jittraporn Wongsa-Ngam ◽  
Nitikorn Noraphaiphipaksa ◽  
Chaosuan Kanchanomai ◽  
Terence G. Langdon
Keyword(s):  
Steady State ◽  
Plastic Strain ◽  
Equal Channel Angular Pressing ◽  
Fem Simulation ◽  
Effective Plastic Strain ◽  
3D Fem ◽  
Cross Sectional ◽  
Angular Pressing ◽  
Strain Homogeneity ◽  
Zr Alloy

A three-dimensional finite element method (3D FEM) simulation was carried out using ABAQUS/Explicit software to simulate multi-pass processing by equal-channel angular pressing (ECAP) of a circular cross-sectional workpiece of a Cu-Zr alloy. The effective plastic strain distribution, the strain homogeneity and the occurrence of a steady-state zone in the workpiece were investigated during ECAP processing for up to eight passes. The simulation results show that a strain inhomogeneity was developed in ECAP after one pass due to the formation of a corner gap in the outer corner of the die. The calculations show that the average effective plastic strain and the degree of homogeneity both increase with the number of ECAP passes. Based on the coefficient of variance, a steady-state zone was identified in the middle section of the ECAP workpiece, and this was numerically evaluated as extending over a length of approximately 40 mm along the longitudinal axis for the Cu-Zr alloy.

Rheo-Forming AZ91D Magnesium Alloy Using Enthalpy Equilibrium Electromagnetic-Stirring Process

2016 ◽  
Vol 256 ◽  
pp. 263-269
Author(s):  
Xiao Li Zhang ◽  
Tong Min Wang ◽  
Chao Zhang
Keyword(s):  
Solid Particle ◽  
Solid Fraction ◽  
Solid Particles ◽  
Electromagnetic Stirring ◽  
Mg Alloy ◽  
Semisolid State ◽  
Pouring Temperature ◽  
Az91d Magnesium Alloy ◽  
Step Effect ◽  
Metal Processing

An enthalpy equilibrium electromagnetic-stirring process was introduced to semisolid metal processing for rheoforming route. AZ91D was die-casted under normally liquid state of Mg alloy, semisolid state of Mg alloy stirred using traditional EM-stirrer and an enthalpy equilibrium EM-Stirrer, respectively. Further step, effect of pouring temperature on microstructures and tensile properties of castings was researched in the introduced process. Experimental results indicated that samples of rheo-diecasted in the introduced process showed globular primary solid particle microstructure and better comprehensive mechanical properties, typical microstructures consisting of globular primary α-Mg grains and pseudoeutectic organization was observed in the castings with low solid fraction, while in higher solid fraction, the microstructure comprised of agglomerating primary solid particles and Mg17Al12 of divorced eutectic. With decreasing pouring temperature, the density of primary solid particles increased greatly, the size of primary solid particle evolved to coarse.

Processing by Equal-Channel Angular Pressing: Potential for Achieving Superplasticity

1999 ◽  
Vol 601 ◽  
Author(s):  
Minoru Furukawa ◽  
Minoru Nemoto ◽  
Zenji Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Strain ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Superplastic Deformation ◽  
Processing Method ◽  
Nanometer Scale ◽  
Strain Rates ◽  
Cross Sectional ◽  
Angular Pressing ◽  
Processing Procedure

AbstractEqual-channel angular (ECA) pressing is a processing procedure whereby a very severe plastic strain is imposed on a sample without any change in the cross-sectional dimensions of the material. This processing method leads to a substantial grain refinement, producing grains which are within the submicrometer or even the nanometer scale. This paper discusses the potential for using this method to prepare materials for superplasticity. The results demonstrate that it is possible to achieve superplastic deformation in selected materials subjected to ECA pressing and, in addition, there is the possibility of extending the superplastic region so that it occurs at very rapid strain rates.

The Modification Research of Al-Ti-B Master Alloy (Progress)

2014 ◽  
Vol 900 ◽  
pp. 105-109 ◽  
Author(s):  
Jun Jun Wang ◽  
Li Mi ◽  
Zhi Liu Hu
Keyword(s):  
Equal Channel Angular Pressing ◽  
Master Alloy ◽  
High Intensity ◽  
Electromagnetic Stirring ◽  
High Intensity Ultrasound ◽  
Existing Problems ◽  
Angular Pressing ◽  
Development Direction ◽  
The Future

This paper reviews several main modification methods of Al-Ti-B master alloy, including high-intensity ultrasound, equal channel angular pressing, conform, and electromagnetic stirring. Attention is directed to the principles and characteristics of various methods, as well as the researches related to Al-Ti-B master alloy. This review also indicates the existing problems of the technology, and the development direction of the modification of Al-Ti-B master alloy in the future.

3D Finite Element Modeling of Molybdenum Equal Channel Angular Pressing

2008 ◽  
Author(s):  
Royi Padan ◽  
David Gorni ◽  
Leonid Rubinson ◽  
Eilon Faran ◽  
Ilan Gilad ◽  
...  
Keyword(s):  
Finite Element ◽  
Elevated Temperature ◽  
Equal Channel Angular Pressing ◽  
Effective Strain ◽  
Hard Metal ◽  
Work Piece ◽  
Element Analysis ◽  
Cross Sectional ◽  
Angular Pressing ◽  
Ecap Process

Equal-channel angular pressing (ECAP) is a manufacturing process in which a material is subjected to a severe plastic shear strain with negligible change in the cross-sectional dimensions of the work-piece. Due to the severe plastic deformation, the ECAP process was investigated experimentally mainly on ductile materials such as Cu-99% and Al-4%Cu. Application of ECAP to harder metals (such as CP-Ti or Mo) imposes several problems due to the elevated temperature involved, cracks that may appear in the material and the large forces required. Furthermore, several cycles of the ECAP are required to obtain a uniform residual strain field in the workpiece. To optimize and gain scientific insight into the ECAP process of a Mo workpiece, a combined experimental–numerical investigation was conducted. A three dimensional finite element analysis (FEA) that simulates an ECAP BC4 process of hard metal at elevated temperature was performed. Both quantitative (final simulated geometry was compared to the shape of the workpiece after ECAP) qualitative (hardness and grain size were compared to effective-strain) methods were used for FE results validation.

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