Effect of rotary-die equal channel angular pressing on the thermoelectric properties of a (Bi,Sb)2Te3 alloy

2005 ◽  
Vol 20 (4) ◽  
pp. 895-903 ◽  
Author(s):  
Z.M. Sun ◽  
H. Hashimoto ◽  
N. Keawprak ◽  
A.B. Ma ◽  
L.F. Li ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Equal Channel Angular Pressing ◽  
Figure Of Merit ◽  
Pulse Discharge ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Ecap Processing ◽  
Figures Of Merit ◽  
Angular Pressing ◽  
Ecap Process

A (Bi,Sb)2Te3 alloy powder was sintered via a pulse discharge sintering process followed by a rotary-die equal channel angular pressing (ECAP) process. It was found by x-ray diffraction analysis that the as-sintered material shows preferentially orientated microstructure, which were considerably eliminated by following ECAP processes. Generally, the Seebeck coefficient of the material was reduced by ECAP processing, which was attributed to the increased carrier concentration after the severe plastic deformation. Electrical conductivity increases after ECAP, which was also originated from the increased carrier concentration. The figure of merit of the material in different conditions shows higher value in the transverse direction. In the transverse samples, those after ECAP processing showed increased figures of merit, which reached 3.85 × 10−3/K in the material after 4 passes of ECAP.

Equal channel angular pressing of wire-formed Al6063 by PU rubber-assisted procedure

2021 ◽  
pp. 030932472110456
Author(s):  
Mahmoud Ebrahimi ◽  
Shokouh Attarilar ◽  
Hatice-Varol Özkavak ◽  
Ceren Gode
Keyword(s):  
Equal Channel Angular Pressing ◽  
X Ray Diffraction ◽  
Angular Pressing ◽  
Ecap Process ◽  
Aluminum Sample ◽  
Deformation Processes ◽  
Dislocations Density ◽  
6063 Aluminum Alloy ◽  
Dislocation Strengthening ◽  
Lattice Microstrain

Expanding suitable severe plastic deformation processes seems essential to design lightweight wire-formed materials for emerging demands. In this regard, 6063 aluminum alloy in the form of wire was processed successfully by polyurethane rubber assisted-equal channel angular pressing up to 16 passes by route BC. It was found that significant improvement of hardness and strength is achieved at the initial passes due to the increment of material’s dislocations density which leads to the crystallite size decrease and lattice microstrain increase. Also, subsequent passes improve the mechanical properties with a gentle rate due to the saturation of dislocation strengthening. The fractography analysis indicated that the ductile fracture mode of the annealed aluminum decreases by imposing the ECAP process. It is related to the formation of cleavage and rive patterns and the reduction in the number and size of the dimples compared to the initial condition. Eventually, X-ray diffraction findings showed that by adding pass numbers, the isotropy degree of the aluminum sample enhances because of the lowest diffraction scattering.

scholarly journals Experimental and Numerical Investigation of the ECAP Processed Copper: Microstructural Evolution, Crystallographic Texture and Hardness Homogeneity

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 607
Author(s):  
A. I. Alateyah ◽  
Mohamed M. Z. Ahmed ◽  
Yasser Zedan ◽  
H. Abd El-Hafez ◽  
Majed O. Alawad ◽  
...  
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Cross Section ◽  
Room Temperature ◽  
Pure Copper ◽  
High Density ◽  
Ecap Processing ◽  
Heterogeneous Distribution ◽  
Angular Pressing ◽  
Average Grain Size

The current study presents a detailed investigation for the equal channel angular pressing of pure copper through two regimes. The first was equal channel angular pressing (ECAP) processing at room temperature and the second was ECAP processing at 200 °C for up to 4-passes of route Bc. The grain structure and texture was investigated using electron back scattering diffraction (EBSD) across the whole sample cross-section and also the hardness and the tensile properties. The microstructure obtained after 1-pass at room temperature revealed finer equiaxed grains of about 3.89 µm down to submicrons with a high density of twin compared to the starting material. Additionally, a notable increase in the low angle grain boundaries (LAGBs) density was observed. This microstructure was found to be homogenous through the sample cross section. Further straining up to 2-passes showed a significant reduction of the average grain size to 2.97 µm with observable heterogeneous distribution of grains size. On the other hand, increasing the strain up to 4-passes enhanced the homogeneity of grain size distribution. The texture after 4-passes resembled the simple shear texture with about 7 times random. Conducting the ECAP processing at 200 °C resulted in a severely deformed microstructure with the highest fraction of submicron grains and high density of substructures was also observed. ECAP processing through 4-passes at room temperature experienced a significant increase in both hardness and tensile strength up to 180% and 124%, respectively.

Processing of Copper by Equal Channel Angular Pressing (ECAP) – Microstructure Investigations

2015 ◽  
Vol 641 ◽  
pp. 286-293
Author(s):  
Beata Leszczyńska-Madej ◽  
Maria W. Richert ◽  
Agnieszka Hotloś ◽  
Jacek Skiba
Keyword(s):  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Subgrain Size ◽  
Pure Copper ◽  
Shear Bands ◽  
Angular Pressing ◽  
Ecap Process ◽  
Transmission Electron ◽  
Different Types ◽  
Diffraction Patterns

The present study attempts to apply Equal-Channel Angular Pressing (ECAP) to 99.99% pure copper. ECAP process was realized at room temperature for 4, 8 and 16 passes through route BC using a die having angle of 90°. The microstructure of the samples was investigated by means both light and transmission electron microscopy. Additionally the microhardness was measured and statistical analysis of the grains and subgrains was performed. Based on Kikuchi diffraction patterns misorientation was determined. There were some different types of bands in the microstructure after deformation. The shear bands, bands and in the submicron range the microshear bands and microbands are a characteristic feature of the microstructure of copper. Also characteristic was increasing of the number of bands with increasing of deformation and mutually crossing of the bands. The intersection of a bands and microbands leads to the formation of new grains with the large misorientation angle. The measured grain/subgrain size show, that the grain size is maintained at a similar level after each stage of deformation and is equal to d = 0.25 – 0.32 μm.

Numerical Simulation of Microstructure Evolution in AZ31 Magnesium Alloy during Equal Channel Angular Pressing

2014 ◽  
Vol 609-610 ◽  
pp. 495-499
Author(s):  
Guo Cheng Ren ◽  
Xiao Juan Lin ◽  
Shu Bo Xu
Keyword(s):  
Finite Element ◽  
Magnesium Alloy ◽  
Equal Channel Angular Pressing ◽  
Microstructure Evolution ◽  
Element Model ◽  
Az31 Magnesium Alloy ◽  
Angular Pressing ◽  
Ecap Process ◽  
Element Simulation ◽  
3D Software

The microstructure and material properties of AZ31 magnesium alloy are very sensitive to process parameters, which directly determine the service properties. To explore and understand the deformation behavior and the optimization of the deformation process, the microstructure evolution during equal channel angular pressing was predicted by using the DEFORM-3D software package at different temperature. To verify the finite element simulation results, the microstructure across the transverse direction of the billet was measured. The results show that the effects strain and deformation temperatures on the microstructure evolution of AZ31 magnesium during ECAP process are significant, and a good agreement between the predicted and experimental results was obtained, which confirmed that the derived dynamic recrystallization mathematical models can be successfully incorporated into the finite element model to predict the microstructure evolution of ECAP process for AZ31 magnesium.

Strength of Commercial Aluminum Alloys after Equal Channel Angular Pressing and Post-ECAP Processing

2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
Ultimate Tensile Strength ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Solution Treatment ◽  
Ecap Processing ◽  
Angular Pressing

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.

scholarly journals Analysis of Tribological Properties in Disks of AA-5754 and AA-5083 Aluminium Alloys Previously Processed by Equal Channel Angular Pressing and Isothermally Forged

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 938
Author(s):  
Carmelo J. Luis Pérez ◽  
Rodrigo Luri Irigoyen ◽  
Ignacio Puertas Arbizu ◽  
Daniel Salcedo Pérez ◽  
Javier León Iriarte ◽  
...  
Keyword(s):  
Equal Channel Angular Pressing ◽  
Aluminium Alloys ◽  
Mean Value ◽  
Wear Behaviour ◽  
Volume Loss ◽  
Angular Pressing ◽  
Ring Configuration ◽  
Ecap Process ◽  
Initial States ◽  
Accumulated Deformation

In the present study, the wear behaviour of two aluminium alloys (AA-5754 and AA-5083) is analysed where these have been previously processed by severe plastic deformation (SPD) with equal channel angular pressing (ECAP). In order to achieve the objectives of this study, several disks made of these alloys are manufactured by isothermal forging from different initial states. The microstructures of the initial materials analysed in this study have different accumulated deformation levels. In order to compare the properties of the nanostructured materials with those which have not been ECAP-processed, several disks with a height of 6 mm and a diameter of 35 mm are manufactured from both aluminium alloys (that is, AA-5754 and AA-5083) isothermally forged at temperatures of 150 and 200 °C, respectively. These thus-manufactured disks are tested under a load of 0.6 kN, which is equivalent to a stress mean value of 18 MPa, and at a rotational speed of 200 rpm. In order to determine the wear values, the disks are weighed at the beginning, at 10,000 revolutions, at 50,000 revolutions and at 100,000 revolutions, and then the volume-loss values are calculated. This study was carried out using specific equipment, which may be considered to have a block-on-ring configuration, developed for testing in-service wear behaviour of mechanical components. From this, the wear coefficients for the two materials at different initial states are obtained. In addition, a comparison is made between the behaviour of the previously ECAP-processed aluminium alloys and those that are non-ECAP-processed. A methodology is proposed to determine wear coefficients for the aluminium alloys under consideration, which may be used to predict the wear behaviour. It is demonstrated that AA-5754 and AA-5083 aluminium alloys improve wear behaviour after the ECAP process compared to that obtained in non-ECAP-processed materials.

scholarly journals PERUBAHAN NILAI KEKERASAN DAN KONDUKTIVITAS LISTRIK ALUMINIUM AKIBAT PROSES EQUAL CHANNEL ANGULAR PRESSING (ECAP)

ROTASI ◽  
2014 ◽  
Vol 16 (4) ◽  
pp. 41
Author(s):  
Rusnaldy Rusnaldy ◽  
Norman Iskandar ◽  
Muhammad Khairul Rais ◽  
Wisnu Tri Erlangga
Keyword(s):  
Electrical Conductivity ◽  
Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Hardness Test ◽  
Hardness Measurement ◽  
Optical Microscope ◽  
Pure Aluminium ◽  
Angular Pressing ◽  
Ecap Process ◽  
Number Of Passes

In current study, Equal Channel Angular Pressing (ECAP) process was applied to pure aluminium rod. The effect of the number of passes on hardness and electrical conductivity ECAP samples was investigated. The dimensions of ECAP die for 12 mmm diameter workpieces are designed with intersect angle of 120o. The experiments were carried out by using samples cut from an ingot and a rod and machined to a size of 12 mm in diameter and 50 mm in length. The workpiece was pressed into the ECAP die up to 7 passes at room temperature.After deformation, all samples were subjected to a hardness test, an electrical conductivity test and for optical microscope study. The hardness measurement of the ECAP samples suggested that enhanced hardness would be obtained by repeating ECAP process.Increasing the electrical conductivity of the ECAP samples indicatesthat there is no dislocation formation due to increasing plastic deformation in ECAP process

Deformation Behavior of Cu-8wt%Ag Alloy during Equal Channel Angular Pressing

2015 ◽  
Vol 1101 ◽  
pp. 93-98
Author(s):  
Yue Shen ◽  
Chuan Ting Ren ◽  
Guo Quan Zhang ◽  
Ming Xie ◽  
Ming Wen ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Equal Channel Angular Pressing ◽  
Deformation Behavior ◽  
Shear Bands ◽  
Vertical Plane ◽  
Vertical Shear ◽  
Ecap Processing ◽  
Angular Pressing ◽  
Micro Level ◽  
The One

The shear deformation behavior of the course-grained Cu-8wt%Ag alloy processed by one pass of equal channel angular pressing (ECAP) was revealed through the metallurgical microscope and the scanning electron microscope. Through the macro-level and micro-level synthesis analysis, it is confirmed that there are two shear deformation during the ECAP processing: the one along the intersection plane (IP) and the other along the vertical plane to the IP. And it is estimated that theoretical ranges of two shear angles are-32°<θ1<0° and 43°<θ2<58° respectively. Finally, it is also proved that the evolution of the shear bands is affected by the parallel and vertical shear to the IP of the ECAP die, and that, besides the shear along the IP, the shear along the vertical plane to the IP also plays an important role during the plastic deformation.

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