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.

Superplastic Behavior in Ultrafine-Grained Materials Produced by Equal-Channel Angular Pressing

2008 ◽  
Vol 579 ◽  
pp. 29-40 ◽  
Author(s):  
Cheng Xu ◽  
Megumi Kawasaki ◽  
Roberto B. Figueiredo ◽  
Zhi Chao Duan ◽  
Terence G. Langdon
Keyword(s):  
Equal Channel Angular Pressing ◽  
High Strain ◽  
Processing Method ◽  
Strain Rates ◽  
Bulk Materials ◽  
Superplastic Behavior ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Ultrafine Grained Materials ◽  
Aluminum And Magnesium Alloys

Equal-channel angular pressing (ECAP) is a convenient processing method for refining the grain size of bulk materials to the submicrometer level. Metallic alloys processed by ECAP often exhibit excellent superplastic characteristics including superplasticity at high strain rates. This paper summarizes recent experiments designed to evaluate the occurrence of superplasticity in representative aluminum and magnesium alloys and in the Zn-22% Al eutectoid alloy.

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.

Grain Refinement and Superplastic Deformation Behavior of Zn-Al Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 1775-1780
Author(s):  
Keun Joon Kim ◽  
Gil Hwan Na ◽  
Tae Kwon Ha
Keyword(s):  
Grain Refinement ◽  
Deformation Behavior ◽  
Superplastic Deformation ◽  
Al Alloys ◽  
Al Alloy ◽  
Strain Rates ◽  
Processing Maps ◽  
Compression Tests ◽  
Angular Pressing ◽  
Fine Grain

Grain refinement and superplastic deformation behavior of Zn-Al alloys were investigated in this study. To obtain fine grain size in Zn-0.3Al alloys, rolling and equal channel angular pressing (ECAP) were conducted at temperatures from 40 to 160°C after casting and homogenization heat treatment. Material processing maps for Zn-0.3Al alloy were constructed from a series of compression tests conducted at temperatures from RT to 200°C and strain rates from 3×10-2 to 101 s-1. Superplasticity of ECAPed specimens were evaluated at the temperature of 100°C under the strain rate of 2×10-4 s-1. After ECAP of the Zn-0.3Al alloy, elongation was dramatically increased up to 500%. The effects of ECAP on the texture and anisotropy in the superplastic deformation bebavior were found to be negligible.

Grain Refinement and Strengthening of a Cylindrical Pure-Aluminum Specimen by Using Modified Equal-Channel Angular Pressing Technique

2007 ◽  
Vol 340-341 ◽  
pp. 937-942 ◽  
Author(s):  
Takuya Yamane ◽  
Ryouji Kondou ◽  
Chobin Makabe
Keyword(s):  
Plastic Strain ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Pure Aluminum ◽  
Hardness Test ◽  
Geometric Transformation ◽  
Aluminum Specimen ◽  
Angular Pressing ◽  
Grain Distribution ◽  
Strengthening Technique

A new grain refinement and strengthening technique by modified ECAP (equal-channel angular pressing) technique was proposed in this study. ECAP technique is an effective technique for grain refinement and strengthening of metal material. This technique gives high shear plastic strain to the material without geometric transformation of the specimen. However, traditional ECAP technique is restricted by material type and size, especially length. Such kinds of restrictions cause various problems in practical use. We modified traditional ECAP dies and processes to allow high plastic strain for long-length pure-aluminum specimens. Then, grain distribution was observed using a microscope, grain size was determined by the Jeffries and the Heyn methods, and strengthening was investigated by micro-Vickers hardness test. Then the effectiveness of proposed grain refinement or strengthening techniques was discussed.

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.

Influence of Stacking Fault Energy on the Microstructures and Grain Refinement in the Cu-Al Alloys during Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 379-384 ◽  
Author(s):  
X.H. An ◽  
Shi Ding Wu ◽  
Z.F. Zhang
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Al Alloys ◽  
Stacking Fault ◽  
High Recovery ◽  
Angular Pressing ◽  
High Recovery Rate ◽  
Refinement Mechanism ◽  
Stacking Fault Energies

The microstructural evolution and grain refinement of Cu-Al alloys with different stacking fault energies (SFEs) processed by equal-channel angular pressing (ECAP) were investigated. The grain refinement mechanism was gradually transformed from dislocation subdivision to twin fragmentation with tailoring the SFE of Cu-Al alloys. Concurrent with the transition of grain refinement mechanism, the grain size can be refined into from ultrafine region (1 m~100 nm) to the nanoscale (<100 nm) and then it is found that the minimum equilibrium grain size decreases in a roughly linear way with lowering the SFE. Moreover, in combination with the previous results, it is proposed that the formation of a uniform ultrafine microstructure can be formed more readily in the materials with high SFE due to their high recovery rate of dislocations and in the materials with low SFE due to the easy formation of a homogeneously-twinned microstructure.

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