Microstructure Evolution of Pure Nickel up to a High Strain Level during Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 319-324 ◽  
Author(s):  
Fan Liu ◽  
Yue Zhang ◽  
Jing Tao Wang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Tensile Tests ◽  
Dislocation Cell ◽  
Pure Nickel ◽  
Strain Level ◽  
Strength Increase ◽  
Angular Pressing ◽  
Cell Structures

Nickel of 99.5% purity, with an initial grain size of ~23 μm, was subjected to equal-channel angular pressing (ECAP) up to a strain of ~12 at room temperature via route Bc. Mechanical properties and microstructures are investigated by tensile tests, microhardness tests, TEM, and EBSD observations. Results of mechanical properties show that yield strength and tensile strength increase as strain increase up to a max value( s~1009 MPa, b~1120 MPa) at ~8, and microhardness reaches its maximum of ~370HV after 12 passes. Analysis by TEM showed that grain size of pure nickel was severely refined from ~23 μm to several hundreds of nanometers after ECAP processing. Initial coarse grain are divided with lamellar boundaries and dislocation cell structures at low strain level, there has resulted in a homogenous and fine spacing of lamellar boundaries (~100 nm) after 4 passes of ECAP, low angle characters of those boundaries are revealed from corresponding SAED pattern; equiaxed grains of diameter with ~98 nm come out among lamellar boundaries after 12 passes.

Microstructures and Mechanical Properties of Fcc Pure Metals with Different Stacking Fault Energies by Equal Channel Angular Pressing

2011 ◽  
Vol 682 ◽  
pp. 193-203 ◽  
Author(s):  
Yue Zhang ◽  
Jin Qiang Liu ◽  
Jing Tao Wang ◽  
Zhi Bin Wu ◽  
Fan Liu
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Equal Channel Angular Pressing ◽  
Pure Aluminum ◽  
Pure Copper ◽  
Pure Nickel ◽  
Strain Level ◽  
Angular Pressing ◽  
Microstructures And Mechanical Properties ◽  
Strain Increase

In the present work 99.98% commercial pure copper, 99.5% commercial pure nickel and 99.5% commercial pure aluminum were imposed on high strain levels of ~24, ~8 and ~44 by equal channel angular pressing (ECAP) via route Bc, respectively. Microstructures and mechanical properties are investigated by TEM observations, tensile tests and microhardness tests. It shows that grain sizes of pure copper, pure nickel and pure aluminum has been severed refined from several tens of microns into several hundreds of nanometers after ECAP processing, however, microstructure of copper are mainly consisted of equiaxed (sub) grains with illegible grains/ (sub) grains boundaries after processed by ECAP, while it is featured as lamellar boundaries in that of pure nickel and as elongated grains in that of pure aluminum underwent a same strain level of ECAP. Results of mechanical properties show that yield strength and microhardness increase as strain increase up to a max value in copper, and then begin to decrease slightly, while mechanical properties of the other two increase as strain increases in nickel up to a strain level of ~12, and as in aluminum, yield strength and microhardness increase as strain increase in a relative low strain level, and then reach an saturation value.

Microstructures and Mechanical Properties of AZ61 Mg Alloy Processed by Equal Channel Angular Pressing

2012 ◽  
Vol 468-471 ◽  
pp. 2124-2127 ◽  
Author(s):  
Shao Feng Zeng ◽  
Kai Huai Yang ◽  
Wen Zhe Chen
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Uniform Elongation ◽  
Considerable Decrease ◽  
Angular Pressing ◽  
Az61 Magnesium Alloy ◽  
Average Grain Size ◽  
Microstructures And Mechanical Properties ◽  
Bimodal Grain Size

Equal channel angular pressing (ECAP) was applied to a commercial AZ61 magnesium alloy for up to 8 passes at temperatures as low as 473K. Microstructures and mechanical properties of as-received and ECAP deformed samples were investigated. The microstructure was initially not uniform with a “bimodal” grain size distribution but became increasingly homogeneous with further ECAP passes and the average grain size was considerably reduced from over 26 μm to below 5 μm. The ultimate tensile strength (UTS) decreases clearly after one pass, but increases significantly up to two passes, and then continuously slowly decreases up to six passes, and again increases slightly up to eight passes. In contrast, the uniform elongation increased significantly up to 3 passes, followed by considerable decrease up to 8 passes. These observations may be attributed to combined effects of grain refinement and texture development.

Microstructure and Mechanical Properties of Mg96Y3Zn1 Alloy Processed by Equal Channel Angular Pressing

2011 ◽  
Vol 682 ◽  
pp. 49-54
Author(s):  
Bin Chen ◽  
Chen Lu ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Equal Channel Angular Pressing ◽  
Ultrafine Grains ◽  
Angular Pressing ◽  
Average Grain Size

The Mg96Y3Zn1 alloy processed by equal channel angular pressing has been investigated. It was found that the Mg96Y3Zn1 alloy processed by ECAP obtained ultrafine grains and exhibits excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy refined to about 400 nm. The highest strengths with yield strength of 381.45MPa and ultimate tensile strength of 438.33MPa were obtained after 2 passes at 623K. It was found that cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test. As a result, the elongation of alloy is decreased with pass number increasing.

scholarly journals Applying Hybrid Equal Channel Angular Pressing (HECAP) to pure copper using optimized Exp.-ECAP die

2021 ◽  
Author(s):  
Serkan Öğüt ◽  
Hasan Kaya ◽  
Aykut Kentli ◽  
Mehmet UÇAR
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Pure Copper ◽  
Mechanical Tests ◽  
Geometric Parameters ◽  
Homogeneous Distribution ◽  
Angular Pressing ◽  
Ecap Process

Abstract Equal channel angular pressing (ECAP), expansion equal channel angular pressing (Exp.-ECAP) and hybrid equal channel angular pressing (HECAP) processes were applied to pure copper specimens within this study. Before the ECAP and HECAP processes, an Exp.-ECAP mold with optimum geometric parameters was produced to be used in these processes. The samples, on which ECAP, Exp.-ECAP and HECAP processes were applied, were subjected to microstructure analysis and mechanical tests, and the effects of these processes were examined. The results obtained showed that the Exp.-ECAP process gave better results in grain refinement and mechanical properties, and the Exp.-ECAP passes applied after the ECAP process within the scope of the HECAP process provided a more homogeneous distribution for grain size and hardness.

Microstructure and Properties of Ti Rods Produced by Multi-Step SPD

2006 ◽  
Vol 503-504 ◽  
pp. 763-768 ◽  
Author(s):  
V.V. Latysh ◽  
Irina P. Semenova ◽  
G.H. Salimgareeva ◽  
I.V. Kandarov ◽  
Yuntian T. Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Stress ◽  
Equal Channel Angular Pressing ◽  
Thermomechanical Treatment ◽  
Ultrafine Grained Structure ◽  
Annealed State ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Cp Ti

This paper studies the effect of combined SPD treatment on microstructure and mechanical properties of semi-products out of CP Ti. The combined processing, consisting of equal-channel angular pressing and further thermomechanical treatment, produced ultrafine-grained rods out of Grade 2 CP Ti with a diameter of 6.5 mm and a length of up to 1 m. It was established that the formation of homogeneous ultrafine-grained structure in Ti rod with α-grain size of about 100 nm allowed to enhance yield stress by 200% in comparison with initial annealed state.

scholarly journals Mechanical Properties of Copper Processed by Equal Channel Angular Pressing

2017 ◽  
Vol 17 (2) ◽  
pp. 124-129
Author(s):  
K. Sülleiová ◽  
B. Ballóková ◽  
M. Besterci ◽  
T. Kvačkaj
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Dynamic Equilibrium ◽  
Pure Copper ◽  
Angular Pressing ◽  
Static Tensile ◽  
Strength And Ductility ◽  
Test Stress

Abstract The development of the nanostructure in commercial pure copper and the strength and ductility after severe plastic deformation (SPD) with the technology of equal channel angular pressing (ECAP) are analysed. Experimental results and analyses showed that both strength and ductility can be increased simultaneously by SPD. The final grain size decreased from the initial 50μm by SPD to 100-300 nm after 10 passes. An increase of the ductility together with an increase of strength caused by SPD are explained by a strong grain refinement and by a dynamic equilibrium of weakening and strengthening, and it is visible on the final static tensile test stress-strain charts.

Dislocation study of ARMCO iron processed by ECAP

2016 ◽  
Vol 1818 ◽  
Author(s):  
Jairo Alberto Muñoz ◽  
Oscar Fabián Higuera ◽  
José María Cabrera
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Dislocation Density ◽  
Deformation Behavior ◽  
Armco Iron ◽  
Tensile Tests ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Cylindrical Samples

ABSTRACTThe aim of this work was to study the deformation behavior of an Armco iron after severe plastic deformation by equal channel angular pressing (ECAP). Particular attention was paid to predict the dislocation density by different approaches like the model proposed by Bergström. Experimental measures of dislocation density by different techniques are used in the discussion. Cylindrical samples of ARMCO iron (8mm of diameter, 60mm of length) were subjected to ECAP deformation using a die with an intersecting channel of Φ=90° and outer arc of curvature of ψ= 37° die. Samples were deformed for up to 16 ECAP passes following route Bc. The mechanical properties of the material were measured after each pass by tensile tests. The original grain size of the annealed iron (70 μm) was drastically reduced after ECAP reaching grain sizes close to 300nm after 16 passes.

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.

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