scholarly journals Effect Of Severe Plastic Deformation On Microstructure Evolution Of Pure Aluminium

2015 ◽  
Vol 60 (2) ◽  
pp. 1437-1440 ◽  
Author(s):  
B. Leszczyńska-Madej ◽  
M.W. Richert ◽  
M. Perek-Nowak
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Subgrain Size ◽  
Bulk Material ◽  
Extrusion Process ◽  
Hydrostatic Extrusion ◽  
Pure Aluminium ◽  
Fine Grained ◽  
Angular Pressing ◽  
Cumulative Strain

AbstractProcesses of severe plastic deformation (SPD) are defined as a group of metalworking techniques in which a very large plastic strain is imposed on a bulk material in order to make an ultra-fine grained metal. The present study attempts to apply Equal-Channel Angular Pressing (ECAP), Hydrostatic Extrusion (HE) and combination of ECAP and HE to 99.5% pure aluminium. ECAP process was realized at room temperature for 16 passes through route Bc using a die having an angle of 90°. Hydrostatic extrusion process was performed with cumulative strain of 2.68 to attain finally wire diameter of d = 3 mm. The microstructure of the samples was investigated by means of transmission and scanning 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. The measured grain/subgrain size show, that regardless the mode of deformation process (ECAP, HE or combination of ECAP and HE processes), grain size is maintained at a similar level – equal to d = 0.55-0.59μm. A combination of ECAP and HE has achieved better properties than either single process and show to be a promising procedure for manufacturing bulk UFG aluminium.

The Influence of Hydrostatic Extrusion on the Microstructure of 6082 Aluminium Alloy

2006 ◽  
Vol 114 ◽  
pp. 145-150 ◽  
Author(s):  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Małgorzata Lewandowska ◽  
Wacław Pachla ◽  
Mariusz Kulczyk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Tensile Strength ◽  
Severe Plastic Deformation ◽  
Light Microscopy ◽  
Aluminium Alloy ◽  
Extrusion Process ◽  
Hydrostatic Extrusion ◽  
Fine Grained

Hydrostatic extrusion can be viewed as one of the methods of Severe Plastic Deformation, SPD, for the fabrication of ultra-fine grained alloys which causes a significant increase in the mechanical properties such as tensile strength and hardness. In the present study the microstructure of 6082 aluminium alloy after hydrostatic extrusion was investigated. Hydroextrusion was performed in three steps with accumulated true strains of 1.34, 2.73 and 3.74 respectively. Microstructural observations were carried out using SEM, TEM and light microscopy. Grain and inclusion sizes, shapes and distribution were investigated in the HE processed samples. The study has shown that the hydrostatic extrusion process results in a profound refinement of both the grain size and the inclusions in 6082 aluminium alloy.

Influence of Experimental Environment on the Enhancement of Ultra Fine Grain Structure with Optimum Ductility of Equal Channel Angular Pressed Copper

2014 ◽  
Vol 592-594 ◽  
pp. 410-415
Author(s):  
A.T. Vijayashakthivel ◽  
T.N. Srikantha Dath ◽  
B. Ravishankar
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Bulk Material ◽  
Grain Structure ◽  
Structural Refinement ◽  
High Deformation ◽  
Die Geometry ◽  
Angular Pressing ◽  
Fine Grain ◽  
Increased Strength

Strengthening the engineering material through Severe Plastic Deformation and associated structural refinement is an established practice. Among the Severe Plastic Deformation process, Equal Channel Angular Pressing (ECAP) assumes a significant place. In this, it is possible to attain even ultra fine grain (UFG) structure through high deformation in bulk material working mode. However ECAPed material suffers lack of ductility, structural inhomogenity and even thermodynamically unstable structure, as evidenced in the published literature on ECAP of copper. The present study on ECAP of commercial purity copper aimed to attain a structure of higher hardness by shedding little ductility is deviated from the past work; in this, commercial quality copper is ECAPed at 3000 C with a die geometry channel angle of 1100 and corner angle of 200 necessitating less local/working stress. During certain number of passes (six passes), the material experiences higher hardness with fair amount of ductility. The material does not exhibit any further strengthening beyond six passes, which is possibly due to dislocations annihilation/recovery. The increased strength and loss of ductility of the material results in degrading the material when it undergoes tenth pass.

Effect of Process Parameters on Microstructure and Mechanical Properties on Severe Plastic Deformation Process of Aa7075-T6 Aluminum Alloy

2012 ◽  
Vol 622-623 ◽  
pp. 705-709 ◽  
Author(s):  
U. Mohammed Iqbal ◽  
V.S. Senthil Kumar
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Equal Channel Angular Extrusion ◽  
Extrusion Process ◽  
Angular Pressing ◽  
Twist Extrusion ◽  
Number Of Passes

Severe plastic deformation is one of the emerging and promising techniques applied to bulk materials to produce fine grain structure with attractive properties. This study aims to investigate the effect of extrusion parameters like extrusion temperature, number of passes on the equal channel angular pressing and twist extrusion forming behavior of AA7075-T6 Aluminum alloy by hot extrusion process. AA7075-T6 samples of 70x28x18 mm cross sections extruded by equal channel angular pressing and twist extrusion process was subjected to microstructure analysis, hardness and tensile tests in order to determine their mechanical properties. As a result of the experiments, it was determined that twist extrusion leads to more grain refinement at high temperatures with more number of passes compared to equal channel angular pressing. SEM micrographs show that there is severe orientation of the grains facilitated by the extrusion process which enhances the strength. The dense banding of the grains had effected in marginal hardness enhancement in the matrix of the specimens processed by twist extrusion and equal channel angular extrusion process.

Influence of Severe Plastic Deformation Induced by HE and ECAP on the Thermo-Physical Properties of Metals

2015 ◽  
Vol 641 ◽  
pp. 278-285
Author(s):  
Jacek Skiba ◽  
Adam Dominiak ◽  
Tomasz S. Wiśniewski ◽  
Wacek Pachla ◽  
Mariusz Kulczyk ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Physical Properties ◽  
Specific Heat ◽  
Pure Copper ◽  
Deformation Method ◽  
Fine Grained ◽  
Angular Pressing ◽  
Fine Grained Structure ◽  
Thermo Physical Properties

The study is aimed at comparing the changes which occur in the microstructure and thermo-physical properties of pure copper (99.9%) and when copper alloyed with chromium and zirconium subjected to severe plastic deformation (SPD). The plastic deformation techniques employed were hydrostatic extrusion (HE), equal channel angular pressing (ECAP), and a combination of these two processes. The materials thus obtained had an ultra-fine-grained structure with the thermo-physical properties differing from those of the untreated materials. It appeared that there is a correlation between the deformation method employed and the thermo-physical properties of the materials, such as diffusivity and specific heat.

Equal Channel Angular Pressing and Torsion of Pure Al Powder in Tubes

2010 ◽  
Vol 97-101 ◽  
pp. 1109-1115 ◽  
Author(s):  
Xiao Xi Wang ◽  
Ke Min Xue ◽  
Ping Li ◽  
Zhan Li Wu ◽  
Qi Li
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Bulk Material ◽  
Full Density ◽  
Powder Materials ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Al Powder ◽  
Set Up

In this work, a new severe plastic deformation technique for preparing bulk fine-grained materials has been developed to achieve higher plasticity of powder materials. This novel technique, named Equal Channel Angular Pressing and Torsion (ECAPT), combines two severe plastic deformation methods: equal channel angular pressing and twist extrusion. With the designed ECAPT set-up, pure Al powder particles were successfully consolidated into full dense bulk material with fine grains at a lower deformation temperature (200°C) by Powder in Tubes-Equal Channel Angular Pressing and Torsion (PITS-ECAPT). After two passes of PITS-ECAPT, the microstructures at X, Y and Z planes of each sample were all sheared and elongated along a certain direction with fine banded structures; the grains were greatly squashed and refined with an average grain size of ~ 11.90µm; the deformed sample reached the full density; the micro-hardness and yield strength achieved 49.9kg/mm2 and 155Mpa respectively, which were significantly higher than those of as-cast annealed pure Al and pure Al powder sintered materials.

Nanostructured Dual Phase Ti-Al through Consolidation of Particles by Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 63-68
Author(s):  
Edward W. Lui ◽  
Wei Xu ◽  
Kenong Xia
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Multiple Scales ◽  
Bulk Material ◽  
Dual Phase ◽  
Two Phase ◽  
Angular Pressing

A two-phase Ti-Al material was fabricated by severe plastic deformation. Particles of finely mixed elemental Ti and Al were mechanically milled and then consolidated by equal channel angular pressing. The bulk material has a unique interpenetrating structure of Ti and Al phases with multiple scales from micro to nano. Compared to its coarse structured counterpart, the multiscale structured material exhibited a significant increase in strength without compromising plasticity.

Effect of Severe Plastic Deformation on Microstructure and Properties of Polycrystalline Aluminium Al99.5

2014 ◽  
Vol 59 (1) ◽  
pp. 313-316 ◽  
Author(s):  
B. Leszczyńska-Madej ◽  
P. Pałka ◽  
M. Richert
Keyword(s):  
Plastic Deformation ◽  
Tensile Strength ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Shear Bands ◽  
Extrusion Direction ◽  
Hydrostatic Extrusion ◽  
Microstructure And Properties ◽  
Angular Pressing ◽  
Aluminium Level

Abstract Polycrystalline aluminium Al99.5 was deformed through the combination of equal-channel angular pressing (ECAP) by B route (4, 8 and 16 passes) and then by the hydrostatic extrusion (HE) using the cumulative way of deformation, just to the achieving the final wire diameter d = 3 mm. The microstructure of samples was investigated by means light microscopy (LM). Additionally the microhardness measurement and the tensile test were performed to determine the level of aluminium hardening. The texture was determined by using the Brucker Advance D8 equipment. The aim of the research was to determine the influence of severe plastic deformation exerted in the process of equal-channel angular pressing (ECAP) and hydrostatic extrusion (HE) on the microstructure and properties of polycrystalline aluminium Al99.5. The microstructure observations both after the HE process and the combination of ECAP + HE revealed the elongated to the extrusion direction grains and numerous bands and shear bands. The bands and shear bands most clearly revealed at the perpendicular section. The performed investigations showed that with the increase of the deformation the aluminium level hardening increase. The highest properties of tensile strength - UTS = 218 MPa and microhardness level HV0.1 = 46 were obtained after 8 ECAP + HE.

Positron Annihilation Studies of Microstructure of Ultra Fine Grained Metals Prepared by Severe Plastic Deformation

2005 ◽  
Vol 482 ◽  
pp. 207-210 ◽  
Author(s):  
Jakub Čížek ◽  
Ivan Procházka ◽  
Bohumil Smola ◽  
Ivana Stulíková ◽  
Radomír Kužel ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Spatial Distribution ◽  
Severe Plastic Deformation ◽  
Positron Annihilation ◽  
Equal Channel Angular Pressing ◽  
High Pressure Torsion ◽  
Positron Annihilation Spectroscopy ◽  
Fine Grained ◽  
Angular Pressing

In the present work, positron annihilation spectroscopy (PAS) is employed for microstructure investigations of various ultra fine grained (UFG) metals (Cu, Ni, Fe) prepared by severe plastic deformation (SPD), namely high-pressure torsion (HPT) and equal channel angular pressing (ECAP). Generally, UFG metals prepared using both the techniques exhibit two kinds of defects introduced by SPD: dislocations and small microvoids. The size of the microvoids is determined from the PAS data. Significantly larger microvoids are found in HPT deformed Fe and Ni compared to HPT deformed Cu. The microstructure of UFG Cu prepared by HPT and ECAP is compared and the spatial distribution of defects in UFG Cu samples is characterized. In addition, the microstructure of a pure UFG Cu prepared by HPT and HPT deformed Cu+Al2O3 nanocomposite (GlidCop) is compared.

Wear Resistance of SPD-Processed Alloys

2010 ◽  
Vol 667-669 ◽  
pp. 1095-1100
Author(s):  
Nong Gao ◽  
Chuan Ting Wang ◽  
Robert J.K. Wood ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Wear Resistance ◽  
Severe Plastic Deformation ◽  
Accumulative Roll Bonding ◽  
Review Paper ◽  
Roll Bonding ◽  
Fine Grained ◽  
Work Related ◽  
Angular Pressing ◽  
Deformation Processes

Various different severe plastic deformation processes (SPD) have been developed to produce ultra-fine grained (UFG) materials during the last two decades. One very important material property that the UFG materials should have for structural materials application is good wear resistance. This review paper presents some recent work related to the wear resistance of materials processed by SPD, in particular for alloys processed by using equal-channel angular pressing (ECAP) and accumulative roll-bonding (ARB).

Severe Plastic Deformation of Commercially Pure Titanium by Rotary-Die Equal Channel Angular Pressing Method

2006 ◽  
Vol 503-504 ◽  
pp. 717-720
Author(s):  
Akira Watazu ◽  
Ichinori Shigematsu ◽  
Aibin Ma ◽  
Yoshinori Nishida ◽  
Yong Jai Kwon ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Pressing Method ◽  
Fine Grained ◽  
Angular Pressing ◽  
Commercially Pure ◽  
Plastic Deformation Process

The commercially pure titanium cylindrical samples with a diameter of 11.5mm and a length of 24mm were processed by a new severe plastic deformation process, called the rotary-die equal channel angular pressing (RD-ECAP), under the condition of 773K, 2.4mm/s punch. By the RD-ECAP, ECAP processes of 1-4 passes were possible without sample removal and the temperature of cp-titanium could be simply controlled. After the RD-ECAP process, the cp-titanium samples had no crack. Fine-grained microstructures were observed in the sample on Y plane. Therefore the samples processed by RD-ECAP were expected to have high mechanical strength.

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