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.

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.

Incremental Equal Channel Angular Pressing for Grain Refinement

2011 ◽  
Vol 674 ◽  
pp. 19-28 ◽  
Author(s):  
Andrzej Rosochowski ◽  
Lech Olejnik
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Angular Pressing ◽  
Process Implementation ◽  
University Of Technology ◽  
Element Simulation ◽  
Ultrafine Grained ◽  
Deformation Processes ◽  
The University

Creating a small amount of ultrafine grained metals by severe plastic deformation, for example using equal channel angular pressing, is possible in many research laboratories. However, industrial production of these materials is lagging behind because of the lack of industrially viable severe plastic deformation processes. One attempt to change this situation is based on the concept of incremental equal channel angular pressing developed by the University of Strathclyde and Warsaw University of Technology. The paper describes the path the researchers took to develop the process starting from finite element simulation, through tool design and process implementation, to material characterisation. Examples of various process configurations, which enable obtaining UFG bars, plates and sheets are given and possible future developments discussed.

Extending Creep and Superplasticity to Materials with Submicrometer Grain Sizes

2007 ◽  
Vol 345-346 ◽  
pp. 539-544
Author(s):  
Megumi Kawasaki ◽  
Cheng Xu ◽  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloys ◽  
Severe Plastic Deformation ◽  
Flow Behavior ◽  
Ultrafine Grain ◽  
Grain Sizes ◽  
Large Samples ◽  
Angular Pressing ◽  
Recent Advances ◽  
Ultrafine Grained

The mechanisms of creep and superplasticity occurring in conventional large-grained materials are now understood reasonably well. However, very recent advances in the processing of theoretically-dense metals with submicrometer grain sizes have provided the opportunity to extend the understanding of flow behavior to include materials where the grains are exceptionally small. Using processing through the application of severe plastic deformation, as in procedures such as equal-channel angular pressing, it is now feasible to fabricate relatively large samples having ultrafine grain sizes in the submicrometer or nanometer range. This paper examines these recent advances and gives examples of the flow behavior in ultrafine-grained aluminum alloys.

Study of Semisolid and ECAP Processes on Al-Fe-Si Alloy - Microstructure and Kinetic Grain Growth

2011 ◽  
Vol 312-315 ◽  
pp. 166-171 ◽  
Author(s):  
D. Azimi-Yancheshmeh ◽  
M. Aghaie-Khafri
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Optical Microscopy ◽  
Grain Growth ◽  
Ultrafine Grain ◽  
Angular Pressing ◽  
Ultrafine Grain Size ◽  
Heat Treated ◽  
Alloy Microstructure

ECAP (Equal Channel Angular Pressing) is one of the useful methods of Severe Plastic Deformation (SPD) to reach ultrafine grain size. ECAP was carried out on Al-Fe-Si alloy. All grains stretched along the ECAP direction. Samples were ECAPed for one pass into an ECAP mold with two equal channels (1 cm × 1 cm) with 90o between them. After ECAP, specimens were heat treated (semisolided) for different times and temperatures for achieving globular grains. Optical microscopy has been used to evaluate the microstructure. By ECAP and semisolid processes, the structure becomes fine and globular. The kinetic grain growth has been studied for this alloy by the calculation of the D = Ktn equation and log(D)-log(t) curves.

Advances in Superplasticity of Ultrafine-Grained Alloys: Recent Research and Development

2016 ◽  
Vol 838-839 ◽  
pp. 23-33 ◽  
Author(s):  
Ruslan Z. Valiev ◽  
Irina P. Semenova
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Superplastic Forming ◽  
Ultrafine Grain ◽  
Strain Rates ◽  
Unusual Behavior ◽  
Angular Pressing ◽  
Ti Alloys ◽  
Ultrafine Grained ◽  
New Applications

Recent studies have revealed that ultrafine-grained (UFG) metals and alloys produced by severe plastic deformation (SPD) can demonstrate extraordinary superplasticity at low temperatures and/or high strain rates. This work presents new results on superplasticity in several UFG Al and Ti alloys focusing on microstructural evolution and strain hardening, as well as the challenges of their application. Grain refinement in these alloys was accomplished using severe plastic deformation techniques, including new modifications of equal channel angular pressing (ECAP). Unusual behavior of UFG alloys originates both from the formation of ultrafine grain by SPD processing as well as the state of grain boundaries in these materials. It is established that superplastic deformation allowed not only to attain their efficient forming, but also to improve the ultrafine-grained structure and to obtain enhanced mechanical properties in the articles produced. The results demonstrate the possibilities of new applications of superplastic forming using bulk nanostructured materials.

THE PROPERTIES OF BULK ULTRAFINE-GRAINED METALS PROCESSED THROUGH THE APPLICATION OF SEVERE PLASTIC DEFORMATION

2012 ◽  
Vol 05 ◽  
pp. 299-306
Author(s):  
TERENCE G. LANGDON
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Elevated Temperatures ◽  
High Pressure Torsion ◽  
Superplastic Forming ◽  
High Strength ◽  
Basic Principles ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Processing Techniques

Processing through the application of severe plastic deformation (SPD) provides a very attractive tool for the production of bulk ultrafine-grained materials. These materials typically have grain sizes in the submicrometer or nanometer ranges and they exhibit high strength at ambient temperature and, if the ultrafine grains are reasonably stable at elevated temperatures, they have a potential for use in superplastic forming operations. Several procedures are now available for applying SPD to metal samples but the most promising are Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT). This paper examines the basic principles of ECAP and HPT and describes some of the properties that may be achieved using these processing techniques.

Mechanical Properties of Ultrafine-Grained Al-Mg Alloy Produced by Severe Plastic Deformation

2017 ◽  
Vol 743 ◽  
pp. 203-206 ◽  
Author(s):  
Alexander A. Kozulin ◽  
Vladimir A. Krasnoveikin ◽  
Vladimir A. Skripnyak ◽  
Evgeny N. Moskvichev ◽  
Valery E. Rubtsov
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Efficiency ◽  
Physical And Mechanical Properties ◽  
Treatment Method ◽  
Mg Alloy ◽  
Complex Investigation ◽  
Angular Pressing ◽  
Ultrafine Grained

This study examines the effect of severe plastic deformation on the physical and mechanical properties of a light structural Al-Mg alloy. Severe plastic deformation has been performed by equal channel angular pressing through a die with an angle of 90° between the channels to produce ultrafine-grained structure in specimens of studied alloy. A complex investigation of the physical and mechanical properties of the processed alloy has been carried out to examine the microstructure and texture, and to measure microhardness, yield stress and ultimate tensile strength. The obtained results demonstrate high efficiency of the chosen treatment method and mode of producing a light ultrafine-grained alloy.

Achieving Superplasticity and Superplastic Forming through Severe Plastic Deformation

2000 ◽  
Vol 634 ◽  
Author(s):  
Minoru Furukawa ◽  
Zenji Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Elevated Temperatures ◽  
Superplastic Forming ◽  
Ultrafine Grain ◽  
Strain Rates ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Large Bulk ◽  
Processing Procedure

ABSTRACTThe application of severe plastic deformation to metals provides a convenient procedure for achieving nanometer and submicrometer microstructures. Several different processing methods are available but Equal-Channel Angular Pressing (ECAP) is especially attractive because it provides an opportunity for preparing relatively large bulk samples. This paper describes the use of ECAP in preparing materials with ultrafine grain sizes and the subsequent properties of these materials at elevated temperatures. It is demonstrated that, provided precipitates are present to retain these small grain sizes at the high temperatures where diffusion is reasonably rapid, it is possible to achieve remarkably high superplastic elongations in the as-pressed materials and there is a potential for making use of this processing procedure to develop a superplastic forming capability at very rapid strain rates.

Sign in / Sign up

Export Citation Format

Share Document