scholarly journals A New Flow Line Function for Modeling Material Trajectory and Textures in Nonequal-Channel Angular Pressing

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
A. Hasani ◽  
L. S. Toth ◽  
Sh. Mardokh Rouhani
Keyword(s):  
Plastic Deformation ◽  
Crystallographic Texture ◽  
Mechanical Performance ◽  
Flow Line ◽  
Texture Evolution ◽  
Pure Aluminum ◽  
Deformation Field ◽  
Plastic Deformation Zone ◽  
Flow Function ◽  
Angular Pressing

One of the most applied severe plastic deformation processes is ECAP (equal-channel angular pressing) which is suitable to produce ultrafine-grained metallic materials with high mechanical performance. A variant of the ECAP process was proposed in 2009, which consists in reducing the diameter of the exit channel of the die; it is named the nonequal-channel angular pressing (NECAP) process. A flow line function was also proposed to describe the material flow and the deformation field during NECAP. In the present work, an improved version of that flow function is presented containing two additional parameters compared to the previously proposed function. The new parameters permit to control precisely the shapes and the positions of the flow lines. The new flow function was applied to 90° NECAP of commercially pure aluminum to characterize the deformation field and the extent of the plastic deformation zone. The crystallographic texture evolution is also simulated using the new function. Excellent agreements with experiments were obtained for both the flow line trajectories and the crystallographic texture.

Study of a modified ECAP die for producing nanostructured Al6060 alloy using 3D finite element simulation

2016 ◽  
Vol 1818 ◽  
Author(s):  
M. A. González-Lozano ◽  
P. Ponce-Peña ◽  
M.A. Escobedo-Bretado ◽  
R.H. Lara-Castro ◽  
B. X. Ochoa-Salazar
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Severe Plastic Deformation ◽  
Tensile Stress ◽  
Deformation Zone ◽  
Plastic Deformation Zone ◽  
Element Analysis ◽  
Ecap Processing ◽  
Angular Pressing ◽  
Element Simulation

ABSTRACTUsing Finite Element Method (FEM) simulations is possible to study the homogeneity of deformation in the Equal Channel Angular Pressing (ECAP) process. In this work an investigation about the influence of a modified die on strain distribution in an ecaped Al6060 alloy was carried out. Due to that, tensile stress occurs in the vicinity of upper surface of the specimen in the severe plastic deformation zone, which increases the cracking and fracture tendency of the specimen and impedes further ECAP processing, the conventional ECAP die was modified to eliminate the tensile stress and enhance the compressive stress in the severe plastic deformation zone and reducing the cracking and fracture tendency of the specimen. Finite element analysis demonstrated that the stress state changes from tensile to strongly compressive when using the modified die. The aim of this study is to evaluate the advantages/disadvantages of the modified ECAP die and processing conditions.

Microstructure and Texture Evolution in Metals and Alloys during Intense Plastic Deformation

2012 ◽  
Vol 715-716 ◽  
pp. 51-60 ◽  
Author(s):  
Alexandre P. Zhilyaev ◽  
Terry R. McNelley ◽  
Oscar A. Ruano
Keyword(s):  
Plastic Deformation ◽  
Grain Refinement ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Texture Evolution ◽  
Pure Aluminum ◽  
Liquid Nitrogen Temperature ◽  
Metals And Alloys ◽  
Work Piece ◽  
Friction Stir

ntense plastic deformation is generally effective in producing grain refinement. IPD methods include equal channel angular pressing/extrusion (ECAP/ECAE), high-pressure torsion (HPT), accumulative roll bonding (ARB), and friction stir processing (FSP), among others. In this work, we summarize the main results on grain refinement by these processing methods and present our own data on microstructure and texture evolution in metals and alloys during ECAP, HPT and FSP. Whereas ECAP and HPT are usually performed with the work piece material initially at room temperature or even at liquid nitrogen temperature to enhance refinement, FSP involves a brief but complex thermomechanical cycle with peak temperatures up to 0.7 0.9 TMelt. Apparently, materials undergo dynamic recrystallization (DRX) during FSP. DRX also occurs also in metals and alloys of low TMeltdue to adiabatic heating during HPT performed at room temperature. The paper is devoted to revisiting of previous as well as new results and a comparative analysis of microstructure and texture evolution in commercially pure aluminum and selected pure metals and alloys during ECAP, HPT and FSP in order to illustrate the limits of grain refinement.

scholarly journals Microstructure and crystallographic texture of Cu-Zn alloys subjected to ECAP and flat rolling

2021 ◽  
Vol 2094 (2) ◽  
pp. 022039
Author(s):  
L I Zaynullina ◽  
I V Alexandrov
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Crystallographic Texture ◽  
Structural Elements ◽  
Deformation Degree ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Flat Rolling ◽  
Stacking Fault Energies ◽  
Zn Alloys

Abstract This paper presents the results of the microstructure and crystallographic texture investigations of the Cu-Zn alloys system with different stacking fault energies (SFE) subjected to severe plastic deformation (SPD) by equal channel angular pressing (ECAP) and subsequent flat rolling. It is shown that ECAP leads to the formation of an ultrafine-grained (UFG) structure. Further flat rolling is accompanied by a decrease in the size of structural elements and the formation of nanoscale twins, which are more likely to be detected in an alloy with a lower SFE. As the deformation degree increases, the main crystallographic textures components of the investigated alloys become Brass and Goss components.

Principles of Nonequal Channel Angular Pressing

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Arman Hasani ◽  
László S. Tóth ◽  
Benoît Beausir
Keyword(s):  
Deformation Process ◽  
Flow Line ◽  
Deformation Field ◽  
Machining Process ◽  
Exit Channel ◽  
Angular Pressing ◽  
Ecap Process ◽  
Plastic Deformation Process ◽  
Hydrostatic Stresses ◽  
The Stability

A variant of the equal channel angular pressing (ECAP) process is examined in this paper where the channels are of rectangular shape with different thicknesses while the widths of the channels are the same. The process is named nonequal channel angular pressing and it is similar to the earlier introduced dissimilar channel angular pressing (DCAP) process. In DCAP, however, the diameters are near values, with the exit channel being slightly larger, while in NECAP, the exit channel is much smaller attributing several advantages to nonequal channel angular pressing (NECAP) with respect to ECAP. In this work an analysis is performed to determine the strain mode in a 90 deg NECAP die. A new flow line function is also presented to better describe the deformation field. The proposed flow line function is validated using finite element simulations. A comparison is made between ECAP and NECAP. Finally, texture predictions are presented for NECAP of fcc polycrystals. The advantages of this severe plastic deformation process are the following: (i) significantly larger strains can be obtained in one pass with respect to the classical ECAP process, (ii) grains become more elongated that enhances their fragmentation, and (iii) large hydrostatic stresses develop that improve the stability of the deformation process for difficult-to-work materials. The results obtained concerning the deformation field are also applicable in the machining process for the plastic strains that imparted into the chips.

Process and Properties on the Precision Forming of Spline Cold Rolling

2010 ◽  
Vol 154-155 ◽  
pp. 191-196 ◽  
Author(s):  
Zhi Qi Liu ◽  
Jian Li Song ◽  
Yong Tang Li ◽  
Xu Dong Li ◽  
Ming Fu Wang
Keyword(s):  
Plastic Deformation ◽  
Cold Rolling ◽  
High Efficiency ◽  
Flow Line ◽  
Metal Flow ◽  
Impact Resistance ◽  
Rolling Process ◽  
Plastic Deformation Zone ◽  
Forming Process ◽  
Involute Spline

Cold rolling precision forming process of spline is one of the high-efficiency, precision and non-chip forming advanced manufacturing technologies. It has the characteristics such as high forming efficiency, energy-saving, low material consumption and better forming properties of components. The principle and the force of involute spline cold rolling precision forming process were analyzed. Forming experiments of involute spline cold rolling were carried out, and the microhardness map of the tooth outline was gained. The rule of the metal flow in the deforming area and the forming mechanics of the microstructure were analyzed. The influence of plastic deformation on the forming properties was also conducted. Experimental results showed that dramatic plastic deformation has taken place on the upper surface of the workpiece during the cold rolling process of spline, while the influence on the inner materials were very small. The grains were distributed as a flow line pattern along the tooth profile, and the grains in the plastic deformation zone presented a fine and long fibrous state. The hardness on the section of the tooth outline is regularly distributed. Compared with the spline components obtained from conventional cutting method, the hardness of the spline was greatly increased, therefore, comprehensive mechanical property such as wear resistance and impact resistance were largely improved. Precision measuring and hardness testing of the tooth outline section showed that the components obtained by the experiments were free of defects, and the application requirement can be satisfied.

scholarly journals Research on Modeling Crystallographic Texture Evolution of Al Alloy 7075

2021 ◽  
Vol 8 ◽  
Author(s):  
Hao Liu ◽  
Man Zhao ◽  
Yufeng Zhou ◽  
Gang Liu
Keyword(s):  
Crystallographic Texture ◽  
Crystallographic Orientation ◽  
Mechanical Performance ◽  
Texture Evolution ◽  
Al Alloy ◽  
Proposed Model ◽  
Input Parameters ◽  
Before And After ◽  
Temperature Rate ◽  
And Performance

Crystallographic texture is related to the anisotropy or isotropy of material physical properties, including mechanical performance. The crystallographic effect in micromachining is more significant than that in macro-processing owing to that the depth of the cut and the grain size are in the same order. It is of great significance to model the crystallographic texture evolution induced by mechanical and thermal load during micro-machining to investigate the surface integrity and performance of the finished product. This study performed hot deformation experiments of Al alloy 7075 (AA7075) under various input parameters, including the temperature, temperature rate, stain rate, and strain, which was designed using the Taguchi method. Following that, crystallographic orientation of the samples before and after the deformation was tested using electron back-scattered diffraction (EBSD). Then, the crystallographic texture evolution was modeled with the parameters obtained by fitting a part of the experimental data. The crystallographic texture evolution of AA7075 under different levels of input parameters is studied and analyzed. Finally, the sensitivity of crystallographic orientation evolution to the process parameter is analyzed. The results indicate that these four input parameters have a significant impact on some crystallographic texture of the specimens. The proposed model is instructive in the future investigation of micromachining and microstructure evolution.

scholarly journals Effect of SFE on the evolution of crystallographic texture in Cu-Zn alloys subjected to severe plastic deformation

2021 ◽  
Vol 2103 (1) ◽  
pp. 012099
Author(s):  
L I Zaynullina ◽  
V D Sitdikov ◽  
G F Sitdikova ◽  
I V Alexandrov
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Computer Modeling ◽  
Crystallographic Texture ◽  
Copper Alloys ◽  
Experimental Investigations ◽  
Slip Systems ◽  
Angular Pressing ◽  
Self Consistent ◽  
Zn Alloys

Abstract Within the framework of experimental investigations and computer modeling using the viscoplastic self-consistent (VPSC) model of a material plastic flow, the regularities of preferential orientations formation were established, the proportion of certain texture components was estimated, and existing slip systems (SS) and twinning systems (TS) were identified for equal-channel angular pressing (ECAP) of copper alloys depending on the stacking fault energy (SFE).

Texture Formation during Severe Plastic Deformation

2005 ◽  
Vol 495-497 ◽  
pp. 785-790 ◽  
Author(s):  
Igor V. Alexandrov ◽  
M.V. Zhilina ◽  
A.V. Scherbakov ◽  
Alexander Korshunov ◽  
P.N. Nizovtsev ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Material Flow ◽  
3D Model ◽  
Texture Evolution ◽  
Pure Copper ◽  
Texture Formation ◽  
Taylor Model ◽  
Angular Pressing ◽  
Self Consistent

The paper represents results of computer modeling of texture formation in pure copper subjected to severe plastic deformation (SPD) realized by equal channel angular pressing (ECAP). Several polycrystalline models, namely the Taylor model, Sachs model, and self-consistent viscous plastic (VPSC) model, were applied and their predictions of texture evolution for different routes and number of ECAP passes were compared. For these calculations, simple shear deformation was used for the deformation realized by ECAP. Using the VPSC model, a single ECAP pass was revisited, but employing a 3D model of material flow, conducted by the variation-difference method, for the ECAP deformation. The influence of the inner and outer radii at the channel intersection and the friction coefficient on the homogeneity of the texture development in the cross section of the bulk ingot was investigated.

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