TECHNOLOGIES FOR MANUFACTURING NANOSTRUCTURED SURFACES

2020 ◽  
Author(s):  
Андрей Дмитриевич Бухтеев ◽  
Виктория Буянтуевна Бальжиева ◽  
Анна Романовна Тарасова ◽  
Фидан Гасанова ◽  
Светлана Викторовна Агасиева
Keyword(s):  
Plastic Deformation ◽  
Surface Modification ◽  
Severe Plastic Deformation ◽  
Pressing Pressure ◽  
Pressure Treatment ◽  
Structured Surfaces ◽  
Nanostructured Surfaces ◽  
Angular Pressing ◽  
Multilayer Composites ◽  
Compaction Of Powders

В данной статье рассматривается применение и технологии получения наноструктурированных поверхностей. Рассмотрены такие методы как компактирование порошков (изостатическое прессование, метод Гляйтера), интенсивная пластическая деформация (угловое кручение, равноканальное угловое прессование, обработка давлением многослойных композитов) и модификация поверхности (лазерная обработка, ионная бомбардировка). This article discusses the application and technology for obtaining nano-structured surfaces. Methods such as compaction of powders (isostatic pressing, Gleiter method), severe plastic deformation (angular torsion, equal-channel angular pressing, pressure treatment of multilayer composites) and surface modification (laser treatment, ion bombardment) are considered.

MULTI-SCALE FINITE ELEMENT SIMULATION OF SEVERE PLASTIC DEFORMATION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1621-1626
Author(s):  
HYOUNG SEOP KIM
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Severe Plastic Deformation ◽  
Constitutive Model ◽  
Dislocation Cell ◽  
Ultrafine Grain ◽  
Angular Pressing ◽  
Element Simulation ◽  
Ultrafine Grain Size ◽  
Ultrafine Grained

The technique of severe plastic deformation (SPD) enables one to produce metals and alloys with an ultrafine grain size of about 100 nm and less. As the mechanical properties of such ultrafine grained materials are governed by the plastic deformation during the SPD process, the understanding of the stress and strain development in a workpiece is very important for optimizing the SPD process design and for microstructural control. The objectives of this work is to present a constitutive model based on the dislocation density and dislocation cell evolution for large plastic strains as applied to equal channel angular pressing (ECAP). This paper briefly introduces the constitutive model and presents the results obtained with this model for ECAP by the finite element method.

Effect of Severe Plastic Deformation and Hardening on the Properties and Failure Mechanisms of Constructional Steel

2019 ◽  
Vol 945 ◽  
pp. 579-584
Author(s):  
Maria Z. Borisova
Keyword(s):  
Plastic Deformation ◽  
Impact Strength ◽  
Severe Plastic Deformation ◽  
Structural Steel ◽  
Negative Impact ◽  
Failure Mechanisms ◽  
Positive Influence ◽  
Constructional Steel ◽  
Angular Pressing ◽  
The Impact

The influence of severe plastic deformation on structural materials has been actively studied in recent years. Undoubtedly is the positive influence of this method on strength characteristics of materials. In addition, it is very interesting to influence of the severe plastic deformation on the mechanisms of fracture. One of the most common methods of severe plastic deformation is equal-channel angular pressing (ECAP). In this paper, the influence of different modes of ECAP on the strength of structural steel was studied. Also, the destruction of steel at different test temperatures was studied in detail. It is shown that the ECAP increases the strength of steel almost twice, but the plasticity of steel is reduced, which leads to fragility. Quenching can remove the negative impact of the ECAP on toughness of the steel and will increase the impact strength several times.

Role of Strain Gradient and Dynamic Transformation on the Formation of Nanocrystalline Structure Produced by Severe Plastic Deformation

2007 ◽  
Vol 539-543 ◽  
pp. 2787-2792 ◽  
Author(s):  
Minoru Umemoto ◽  
Yoshikazu Todaka ◽  
Jin Guo Li ◽  
Koichi Tsuchiya
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Strain Gradient ◽  
High Pressure Torsion ◽  
Large Strain ◽  
Nanocrystalline Structure ◽  
Angular Pressing ◽  
Dynamic Transformation ◽  
Fine Grained Structure

Formation of nanocrystalline structure by severe plastic deformation has studied extensively. Although ultra fine grained structure (grain size larger than 100 nm) had been obtained in many processes such as heavy cold rolling, equal channel angular pressing (ECAP) or accumulative roll bonding (ARB), the formation of nano grained structure (< 100 nm) is limited to processes such as ball milling, shot peening or drilling. In the present study, high pressure torsion (HPT) deformation and drilling were carried out to understand the conditions necessary to obtain nano grained structure in steels. The results of HPT experiments in pure Fe showed that HPT has superior ability of strengthening and grain refinement probably due to a strain gradient but the saturation of grain refinement occurs before reaching nano grained structure. Drilling experiments in high carbon martensitic steel revelaed that nano grained ferrite forms at the drilled hole surface only when the transformation from ferrite to austenite takes place during drilling. Considering various other processes by which nano grained ferrite was produced, it is proposed that heavy strains with large strain gradients together with dynamic transformation are necessary to reach nano grained ferrite structure.

Severe Plastic Deformation of Al-15Zn-2Mg Alloy: Effect on Wear Properties

2019 ◽  
Vol 803 ◽  
pp. 22-26
Author(s):  
G.K. Manjunath ◽  
K. Udaya Bhat ◽  
G.V. Preetham Kumar
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Wear Test ◽  
Zinc Content ◽  
Wear Properties ◽  
Significant Drop ◽  
Angular Pressing ◽  
First Pass ◽  
Alloy Effect

In the present work, Al-Zn-Mg alloy having highest zinc content was deformed by one of the severe plastic deformation (SPD) technique, equal channel angular pressing (ECAP) and effect of ECAP on the microstructure evolution and the wear properties were studied. ECAP was performed in a split die and the channels of the die are intersecting at an angle of 120º. ECAP was attempted at least possible temperature and the alloy was successfully ECAPed at 423 K. Below this temperature samples were failed in the first pass itself. After ECAP, significant drop in the grain size was reported. Also, ECAP leads to significant raise in the microhardness of the alloy. Predominantly, after ECAP, upsurge in the wear resistance of the alloy was noticed. To figure out the response of ECAP on the wear properties of the alloy; worn surfaces of the wear test samples were analyzed in SEM.

Superplasticity in a 5024 Aluminium Alloy Processed by Severe Plastic Deformation

2012 ◽  
Vol 735 ◽  
pp. 353-358 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Tagirova ◽  
Rustam Kaibyshev
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Initial Strain Rate ◽  
Strain Rates ◽  
Superplastic Behaviour ◽  
Angular Pressing ◽  
Elongation To Failure ◽  
Zr Alloy

The superplastic behaviour of an Al-4.6%Mg-0.35%Mn-0.2%Sc-0.09%Zr alloy was studied in the temperature range 250-500°C at strain rates ranging from 10-4 to 10-1 s-1. The AA5024 was subjected to equal channel angular pressing (ECAP) at 300°C up to ~12. The highest elongation-to-failure of ∼3300% was attained at a temperature of 450°C and an initial strain rate of 5.6×10-1 s-1. Regularities of superplastic behaviour of the 5024 aluminium alloy are discussed.

scholarly journals The Influence of Severe Plastic Deformation and Subsequent Annealing on the Microstructure and Hardness of a Cu–Cr–Zr Alloy

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2241 ◽  
Author(s):  
Garima Kapoor ◽  
Tibor Kvackaj ◽  
Anita Heczel ◽  
Jana Bidulská ◽  
Róbert Kočiško ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
Crystallite Size ◽  
Liquid Nitrogen Temperature ◽  
Apparent Contradiction ◽  
Angular Pressing ◽  
Cu Alloy ◽  
Average Size ◽  
Number Of Passes

A Cu–1.1%Cr–0.04%Zr (wt.%) alloy was processed by severe plastic deformation (SPD) using the equal channel angular pressing (ECAP) technique at room temperature (RT). It was found that when the number of passes increased from one to four, the dislocation density significantly increased by 35% while the crystallite size decreased by 32%. Subsequent rolling at RT did not influence considerably the crystallite size and dislocation density. At the same time, cryorolling at liquid nitrogen temperature yielded a much higher dislocation density. All the samples contained Cr particles with an average size of 1 µm. Both the size and fraction of the Cr particles did not change during the increase in ECAP passes and the application of rolling after ECAP. The hardness of the severely deformed Cu alloy samples can be well correlated to the dislocation density using the Taylor equation. Heat treatment at 430 °C for 30 min in air caused a significant reduction in the dislocation density for all the deformed samples, while the hardness considerably increased. This apparent contradiction can be explained by the solute oxygen hardening, but the annihilation of mobile dislocations during annealing may also contribute to hardening.

scholarly journals Biocomposites Produced from Hardwood Particles by Equal Channel Angular Pressing Without Additives

2019 ◽  
Vol 3 (2) ◽  
pp. 36
Author(s):  
Yu Bai ◽  
Xiaoqing Zhang ◽  
Kenong Xia
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Crack Formation ◽  
Cell Deformation ◽  
Processing Conditions ◽  
Ongoing Research ◽  
Angular Pressing ◽  
Wood Particles

Equal channel angular pressing (ECAP) has been shown to be a promising method for producing biocomposites from wood particles. However, severe plastic deformation during ECAP would cause considerable cracking when consolidation is carried out without a binder. In this study, the processing conditions were investigated for ECAP of hardwood particles into bulk biocomposites without any additives. Crack formation and wood cell deformation were examined in conjunction with thermal stability and crystallinity of the biocomposites. In comparison with hot pressing without severe shearing, a decrease in crystallinity and severe deformation of wood cells occurred during ECAP. Improved processability and homogeneous deformation would occur at high ECAP temperature (e.g., 210 °C) or low ECAP speed (e.g., 10 mm/min), leading to reduced crack formation in the ECAP-produced biocomposites. Despite its tendency to cause periodic cracking, effective plastic deformation in the regions between cracks was shown to improve interparticle binding. Ongoing research points to the potential achievement of crack-free hardwood (HW) consolidated without a binder, leading to significantly enhanced strength.

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.

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