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.

Finite Element Simulation of Heat Transfer during Cryogenic Asymmetric Sheet Rolling of Aluminum Alloys

2016 ◽  
Vol 716 ◽  
pp. 692-699 ◽  
Author(s):  
Alexander Pesin ◽  
Denis Pustovoytov
Keyword(s):  
Heat Transfer ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Severe Plastic Deformation ◽  
Grain Structure ◽  
Sheet Rolling ◽  
Fine Grain ◽  
Element Simulation ◽  
Alloy 6061

Aluminum and its alloys are widely used as structural materials in aerospace, automotive and other industries due to low density and high specific strength. Efficient way to increase strength and other properties of aluminum alloys is to form an ultra fine grain structure using severe plastic deformation methods. Cryogenic asymmetric sheet rolling under liquid nitrogen temperature is a process of severe plastic deformation that can be used to improve the aluminum alloys structure and properties. Prediction of sheet temperature during plastic deformation is very important. The temperature of sheet is changed due to the conversion of mechanical work of deformation into heat through sliding on contact surfaces. This paper presents the results of the finite element simulation of heat transfer during cryogenic asymmetric sheet rolling of aluminum alloy 6061. The effect of thickness reduction, rolling velocity and friction coefficient on the deformation heating and temperature field of aluminum alloy 6061 was found. The results of investigation could be useful for the development of the optimal treatment process of aluminum alloys by cryogenic severe plastic deformation to obtain the ultra fine grain structure and high strength properties.

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.

Equal Channel Angular Pressing of Al Alloy AA2219

2009 ◽  
Vol 67 ◽  
pp. 53-58
Author(s):  
V. Anil Kumar ◽  
M.K. Karthikeyan ◽  
Rohit Kumar Gupta ◽  
P. Ramkumar ◽  
P.P. Sinha
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
High Strength ◽  
Dark Field ◽  
Grain Structure ◽  
Al Alloy ◽  
Angular Pressing

Severe plastic deformation processes (SPD) are gaining importance as advanced materials processing techniques and hold immense potential in obtaining ultra fine-grained high strength materials. Among the SPD techniques, Equal channel angular pressing (ECAP) has its own merits to produce materials with ultra fine grains in bulk with better mechanical properties. The material deforms with high level of plastic strain inside the channel resulting in grain refinement of the output material with improvement in mechanical properties. A very viable die configuration was conceptualized and die was made with 1200 channel angle. Processing of 25 mm dia. of Al alloy AA2219 at room temperature was successfully carried out and grain refinement was observed. The mechanism of grain refinement has been studied using optical and transmission electron microscopy (TEM). It was observed that low energy dislocation structure (LEDS) forms concurrently with sub-grain structure due to dislocation rearrangements, which provide stability to the evolving sub-grain structure. Dislocation mobility is hindered by the presence of precipitates and / or intermetallic dispersoids present in the matrix and results in presence of dislocations in grain interiors. The pile up of dislocations at intermetallic dispersoids was confirmed from the dark field TEM micrographs. Present paper describes the experimental procedure and followed to attain severe plastic deformation through ECAP. Increase in hardness as well as refinement in the grain size after 5-passes have been discussed in light of extensive optical and TEM. The mechanisms of grain refinement to achieve nano-grained structure and strengthening accrued from the grain refinement through ECAP has been discussed.

Fatigue of Ultra-Fine Grained α-Brass

2014 ◽  
Vol 891-892 ◽  
pp. 1125-1130
Author(s):  
Yoshikazu Nakai ◽  
Takuto Imanaka ◽  
Daiki Shiozawa
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Severe Plastic Deformation ◽  
Fatigue Limit ◽  
High Strength ◽  
Angular Pressing ◽  
Fine Grain ◽  
Proof Strength

Combined methods to obtain ultra-fine grain (UFG) α-brass samples are proposed. Severe plastic deformation followed by recrystallization was conducted, where multiple rolling and equal channel angular pressing (ECAP) were employed. Recrystallization was accomplished by heat-treatment after the severe plastic deformation, and the grain size after the severe plastic deformation was decreased. By multiple rolling, plates with thickness of 0.1 mm and grain size of 1.0 μm were obtained. By ECAP process, square bar with cross-section of 6 mm × 6 mm and minimum grain size of 4.1 μm was obtained. The 0.2 % proof strength, ultimate tensile strength, and fatigue limit were increased with the value of inverse square root of grain size (Hall-Petch relationship). Then, the 0.2 % proof strength of UFG brass was tenfold, the ultimate tensile strength and the fatigue limit were two fold increases from the conventional α-brass. Because of the high strength, the scatter of fatigue strength of UFG brass was large, which reflects the sensitivity to defects in material.

Determination of Mechanical Properties on Aluminium with 5% Copper Powder Metallurgy Route Compacts through Equal Channel Angular Pressing

2015 ◽  
Vol 813-814 ◽  
pp. 161-165
Author(s):  
M. Sadhasivam ◽  
T. Pravin ◽  
S. Raghuraman
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
High Strength ◽  
Angular Pressing ◽  
Fine Grain ◽  
Plastic Deformation Process

The need for super-plasticity and high strength leads to the development of Severe Plastic Deformation technique. The strength of the material is directly dependent upon the grain size of the material. So, there is a need for producing Ultra-Fine Grain microstructure (UFG). UFG material is the material with very small grain size in the range of sub-micrometre. Application of severe plastic deformation, imparts extremely high strain. Equal channel angular pressing (ECAP) is a severe plastic deformation process in which the metal specimen is pressed through an angular channel of equal cross section. The material is subjected to shear deformation and strain is imparted in the specimen. Geometric parameters such as channel angle and corner angle play a major role in grain refinement. Aluminium (Al) specimens are subjected to undergo severe plastic deformation. Since, the strength of Al is not high, other materials are added in order to enhance its mechanical properties by matrix work hardening. Copper (Cu) along with Al shows increase in its strength and also in hardness. An attempt is made with Aluminium and copper, blended in the ratio 95:5 by weight with the main objective to study the Tensile strength, Hardness and Percentage Elongation properties of the specimen.

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.

Structure and Properties of Mg-Al-Ca Alloy after Severe Plastic Deformation

2008 ◽  
Vol 584-586 ◽  
pp. 559-564 ◽  
Author(s):  
Sergey V. Dobatkin ◽  
Yuri Estrin ◽  
L.L. Rokhlin ◽  
Mikhail V. Popov ◽  
Rimma Lapovok ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Nanocrystalline Structure ◽  
Grain Structure ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Different Types ◽  
Lower Temperature

Severe plastic deformation of a Mg-Al-Ca alloy resulted in different types of grain structure. High pressure torsion (HPT) was shown to lead to the formation of a nanocrystalline structure with a grain size of 100-200 nm, while equal channel angular pressing (ECAP) produced ultrafine grained (UFG) or submicrocrystalline (SMC) structures, depending on the ECAP temperature. An UFG structure with a grain size of 2-5 -m was formed at 300°C, as distinct from a finer SMC structure with a grain size of 300-800 nm formed at a lower temperature (220°C). The possibility of increasing the strength of the alloy in the UFG condition by a factor of 1.5-2, combined with a reasonable level of ductility and enhanced functional properties was thus demonstrated. ECAP of annealed Mg-Al-Ca with the formation of UFG structure was shown to lead to increased yield strength (by a factor of 2) and enhanced tensile ductility (by a factor of 3).

Modeling and Analysis on Influence of Channel Angle and Processing Route in Equal Channel Angular Pressing

2014 ◽  
Vol 592-594 ◽  
pp. 504-510 ◽  
Author(s):  
R. Venkatraman ◽  
S. Raghuraman ◽  
Kumar K.S. Ajay ◽  
R. Balaji ◽  
M. Viswanath
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Processing Route ◽  
Modeling And Analysis ◽  
Channel Angle ◽  
Angular Pressing ◽  
Fine Grain ◽  
Optimum Channel ◽  
Deform 3D

Equal Channel Angular Pressing is a severe plastic deformation technique to produce Ultra Fine Grain (UFG) microstructure in bulk materials. The strain induced due to the severe plastic deformation depends mainly upon the channel angle and the processing route followed. Various dies with different channel angle are modeled and analyzed through DEFORM 3D. The strain imparted and the load required for different channel angles and different processing routes are determined from the analysis results. The results are compared and the optimum channel angle is determined.

Effect of Equal Channel Angular Pressing and Post Heating on Microstructure and Hardness of Cu-Zn 70/30

2013 ◽  
Vol 789 ◽  
pp. 373-378 ◽  
Author(s):  
Suryadi Suryadi ◽  
R.A.M. Napitupulu ◽  
Dedi Priadi ◽  
Amin Suhadi ◽  
Eddy S. Siradj
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Optical Microscopy ◽  
Equal Channel Angular Pressing ◽  
Hardness Test ◽  
Grain Structure ◽  
Micro Hardness ◽  
Microstructure Change ◽  
Angular Pressing

Severe plastic deformation (SPD) using various pass number of Equal Channel Angular Pressing (ECAP) experiment and followed heating at 400°C has been done for rod brass Cu-Zn 70/30 to investigate the operation on microstructure and hardness of the alloy. Optical microscopy and SEM are used to examine the microstructure change. Mechanical testing such as macro and micro hardness test is used in order to examine the change of mechanical properties. The grain structure of the alloy was refined from 34 μm to 2 μm after 4 passes ECAP and increased to 4 μm after post heating. The hardness of the alloy significantly increased from 78 Hv to 235 Hv after 4 passes and decreased to 135 Hv after post heating after ECAP. The microstructure and mechanical properties of the alloy was homogenous after 4 passes ECAP because the strain was found more homogenous.

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