Fracture by Microscopic Plastic Deformation Processes

2009 ◽  
pp. 59-59-30 ◽  
Author(s):  
CD Beachem ◽  
DA Meyn
Keyword(s):  
Plastic Deformation ◽  
Deformation Processes

Characterization of residual stresses generated during inhomogeneous plastic deformation

1998 ◽  
Vol 33 (3) ◽  
pp. 243-252 ◽  
Author(s):  
T Lorentzen ◽  
T Faurholdt ◽  
B Clausen ◽  
J Danckert
Keyword(s):  
Plastic Deformation ◽  
Neutron Diffraction ◽  
Residual Stresses ◽  
Numerical Technique ◽  
Numerical Approach ◽  
Explicit Finite Element ◽  
Numerical Predictions ◽  
Deformation Processes ◽  
Elastic Strains

Residual stresses generated by macroscopic inhomogeneous plastic deformation are predicted by an explicit finite element (FE) technique. The numerical predictions are evaluated by characterizing the residual elastic strains by neutron diffraction using two different ( hkl) reflections. Intergranular residual elastic strains between subsets of grains are predicted numerically and verified by neutron diffraction. Subsequently, the measured residual strain profiles in the test samples are modified by the intergranular strains and compared to the engineering predictions of the FE technique. Results compare well and verify the capability of the numerical technique as well as the possibilities of experimental validation using neutron diffraction. The presented experimental and numerical approach will subsequently be utilized for the evaluation of more complicated plastic deformation processes resembling forming operations.

Texture Aspects of Deformation Processes under Equal-Channel Angular Pressing of Metals

2007 ◽  
Vol 561-565 ◽  
pp. 835-838
Author(s):  
Yuriy Perlovich ◽  
Margarita Isaenkova ◽  
Vladimir Fesenko ◽  
M. Grekhov
Keyword(s):  
Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Structure Condition ◽  
Angular Pressing ◽  
Grain Fragmentation ◽  
Deformation Processes ◽  
Distinguishing Features ◽  
Source Of Information ◽  
Mechanisms Of Plastic Deformation ◽  
Loading Scheme

The texture of Ti and Zr rods, subjected to equal-channel angular pressing (ECAP) by routes C and BC, is considered as a source of information about the actual loading scheme, operating mechanisms of plastic deformation, the structure condition of material. Processes of grain reorientation under rolling and ECAP are compared and distinguishing features of the latter are revealed. Effects of grain fragmentation and dynamic recrystallization on the texture are discussed.

Prediction of the Stress-Strain Response of the Ultrafine-Grained Materials Using Multi-Scale Analysis

2010 ◽  
Author(s):  
Mihaela Banu ◽  
Mitica Afteni ◽  
Alexandru Epureanu ◽  
Valentin Tabacaru
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Scale Analysis ◽  
Multi Scale ◽  
Ultrafine Grained ◽  
Deformation Processes ◽  
Ultrafine Grained Materials ◽  
Multi Scale Analysis

There are several severe plastic deformation processes that transform the material from microsized grains to the nanosized grains under large deformations. The grain size of a macrostructure is generally 300 μm. Following severe plastic deformation it can be reached a grain size of 200 nm and even less up to 50 nm. These structures are called ultrafine grained materials with nanostructured organization of the grains. There are severe plastic deformation processes like equal angular channel, high pressure torsion which lead to a 200 nm grain size, respectively 100 nm grain size. Basically, these processes have a common point namely to act on the original sized material so that an extreme deformation to be produced. The severe plastic deformation processes developed until now are empirically-based and the modeling of them requires more understanding of how the materials deform. The macrostructural material models do not fit the behavior of the nanostructured materials exhibiting simultaneously high strength and ductility. The existent material laws need developments which consider multi-scale analysis. In this context, the present paper presents a laboratory method to obtain ultrafine grains of an aluminum alloy (Al-Mg) that allows the microstructure observations and furthermore the identification of the stress–strain response under loadings. The work is divided into (i) processing of the ultrafine-grained aluminum alloy using a laboratory-scale process named in-plane controlled multidirectional shearing process, (ii) crystallographic analysis of the obtained material structure, (iii) tensile testing of the ultrafine-grained aluminum specimens for obtaining the true stress-strain behavior. Thus, the microscale phenomena are explained with respect to the external loads applied to the aluminum alloy. The proposed multi-scale analysis gives an accurate prediction of the mechanical behavior of the ultrafine-grained materials that can be further applied to finite element modeling of the microforming processes.

Sign in / Sign up

Export Citation Format

Share Document