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.

Investigations on Microstructure Evolution and Deformation Behavior of Aged and Ultrafine Grained Al-Zn-Mg Alloy Subjected to Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 253-258
Author(s):  
Wei Ping Hu ◽  
Si Yuan Zhang ◽  
Xiao Yu He ◽  
Zhen Yang Liu ◽  
Rolf Berghammer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Deformation Mechanisms ◽  
Mg Alloy ◽  
Ultrafine Grained

An aged Al-5Zn-1.6Mg alloy with fine η' precipitates was grain refined to ~100 nm grain size by severe plastic deformation (SPD). Microstructure evolution during SPD and mechanical behaviour after SPD of the alloy were characterized by electron microscopy and tensile, compression as well as nanoindentation tests. The influence of η' precipitates on microstructure and mechanical properties of ultrafine grained Al-Zn-Mg alloy is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.

Influence of Severe Plastic Deformation on the PLC Effect and Mechanical Properties in Al 5XXX Alloy

2006 ◽  
Vol 114 ◽  
pp. 171-176 ◽  
Author(s):  
Joanna Zdunek ◽  
Pawel Widlicki ◽  
Halina Garbacz ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
True Strain ◽  
Tensile Tests ◽  
Size Reduction ◽  
Hydrostatic Extrusion ◽  
Stress Strain ◽  
Chatelier Effect

In this work, Al-Mg-Mn-Si alloy (5483) in the as-received and severe plastically deformed states was used. Plastic deformation was carried out by hydrostatic extrusion, and three different true strain values were applied 1.4, 2.8 and 3.8. All specimens were subjected to tensile tests and microhardness measurements. The investigated material revealed an instability during plastic deformation in the form of serration on the stress-strain curves, the so called Portevin-Le Chatelier effect It was shown that grain size reduction effected the character of the instability.

Effect of Grain Size on Mechanical Properties of Mg-0.3at.%Y Dilute Alloy

2018 ◽  
Vol 941 ◽  
pp. 790-795
Author(s):  
Rui Xiao Zheng ◽  
Ichiro Kawarada ◽  
Wu Gong ◽  
Akinobu Shibata ◽  
Hidetoshi Somekawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
High Pressure Torsion ◽  
Tensile Elongation ◽  
Tensile Tests ◽  
Subsequent Annealing ◽  
High Yield ◽  
Grain Sizes ◽  
Mean Grain Size

In this study, a Mg-0.3at.%Y alloy was provided for a severe plastic deformation by high pressure torsion (HPT) and subsequent annealing. After the HPT by 5 rotations, nanocrystalline structures with a mean grain size of 0.23 μm having deformed characteristics were obtained. Fully recrystallized microstructures with mean grain sizes ranging from 0.66 μm to 32.7 μm were obtained by subsequent annealing at various temperatures. Room temperature tensile tests revealed that ultrafine grained (UFG; grain sizes smaller than 1 μm) specimen exhibited very high yield strength over 250 MPa but limited ductility. In contrast, good balance of strength and ductility was realized in fine grained specimens with grain sizes around 2~5 μm. Particularly, the yield strength and total tensile elongation of a specimen with a mean grain size of 2.13 μm were 184 MPa and 37.1%, respectively, which were much higher than those of pure Mg having a similar grain size. The significant effects of grain size and Y addition on the mechanical properties were discussed.

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.

Study of Machining-Induced Microstructure Variations of Nanostructured/Ultrafine-Grained Copper Using XRD

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Yong Huang ◽  
Mason Morehead
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Dislocation Density ◽  
Equal Channel Angular Extrusion ◽  
Outer Radius ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
Ultrafine Grained ◽  
Area And Volume

Various methods for the production of bulk nanostructured (NS)/ultrafine-grained (UFG) materials have been developed, including equal channel angular extrusion (ECAE), a form of severe plastic deformation. Using an ECAE NS/UFG copper bar as an example, this study has investigated machining-induced workpiece microstructure variation using X-ray diffraction. It has been found that (1) under gentle cutting conditions, there was a 10% increase in the median grain size compared with unmachined ECAE NS/UFG copper bars. Increases in the arithmetic-, area-, and volume-weighted grain sizes were found to be 10%, 8%, and 8%, respectively, and (2) an average 27% drop in the dislocation density was observed between the machined and unmachined ECAE copper bars. The dislocation density was shown to have the most reduction (−39%) at the outer radius of the machined ECAE bar where more heat and/or higher pressure were experienced.

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.

Mechanical Properties of Thin Film Aluminum Fibers: Grain Size Effects

1990 ◽  
Vol 188 ◽  
Author(s):  
James E. Steinwall ◽  
H. H. Johnson
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Size Effects ◽  
Rate Sensitivity ◽  
Deformation Mechanisms ◽  
Grain Sizes ◽  
Diffusion Controlled ◽  
Mechanical Strengths

ABSTRACTThin film aluminum fibers with grain sizes of 35 and 100 nm were pulled in a microtensile tester. The larger grains led to greater yield and tensile strengths but smaller strains to failure. Both samples had mechanical strengths 3–6 times greater than bulk aluminum. In addition, the small grained fibers had a strain rate sensitivity exponent of 0.26 suggesting diffusion controlled plastic deformation mechanisms.

Optimization of Strength and Ductility in Ultra-Fine 304 Stainless Steel after Equal-Channel Angular Processing

2010 ◽  
Vol 667-669 ◽  
pp. 937-942 ◽  
Author(s):  
Z.J. Zheng ◽  
Yan Gao ◽  
Y. Gui ◽  
M. Zhu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Stainless Steel ◽  
Dislocation Density ◽  
Vickers Hardness ◽  
304 Stainless Steel ◽  
Angular Pressing ◽  
Equal Channel Angular Processing ◽  
Strength And Ductility

The microstructure and mechanical properties of 304 stainless steel were investigated which was subjected to equal channel angular pressing (ECAP). Tensile strength, elongation, Vickers hardness of as-ECAPed and annealed ECAPed 304 stainless steel were systematically measured and compared and microstructure evolution during ECAP and ECAP+annealing was observed by OM and TEM. It was found that with the increasing of ECAP passes, the grain size of stainless steel was effectively refined to nanoscale, such as about 50 nm after 8 ECAP-passes. In addition, the dislocation density in ECAPed samplel increased greatly, consequently, the tensile strength and hardness of ECAPed 304 stainless steel increased and elongation decreased remarkably. After annealing at 600°C for 10 min，the ductility of ECAPed stainless steel was improved greatly while grains did not have obvious growth, and strength did not change much. The above results showed that the optimization of strength and ductility in ultra-fined 304 stainless steel can be achieved by appropriate ECAP plus annealing processes.

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.

Mechanical Properties of Aluminium Processed by ECAP

2006 ◽  
Vol 114 ◽  
pp. 39-44
Author(s):  
Rafal M. Molak ◽  
Zbigniew Pakiela
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Room Temperature ◽  
Tensile Tests ◽  
Large Plastic Strain ◽  
Angular Pressing ◽  
Purity Aluminium ◽  
High Purity Aluminium ◽  
The Relationship

The aim of this study was to investigate the influence of large plastic strain on the microstructure and mechanical properties of aluminium processed by severe plastic deformation (SPD) by the Equal Channel Angular Pressing (ECAP) method. Polycrystalline high purity aluminium (99,99%) was pressed at room temperature to produce samples subjected to 4, 8 and 12 ECAP passes. The microstructure of aluminium was examined using a light polarized microscope. Microhardness measurements and tensile tests were undertaken to determine the mechanical properties of the material processed by ECAP. The results obtained show the relationship between the microstructure and the mechanical properties of the material.

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