Plastic instability and Lüders bands in the tensile test: the role of crystal orientation

2003 ◽  
Vol 358 (1-2) ◽  
pp. 17-25 ◽  
Author(s):  
H.P. Stüwe ◽  
L.S. Tóth
Keyword(s):  
Tensile Test ◽  
Crystal Orientation ◽  
Plastic Instability ◽  
Lüders Bands

Direct switching of polarization vortex in triangular ferroelectric nanodots: Role of crystal orientation

2021 ◽  
Vol 104 (2) ◽  
Author(s):  
Le Van Lich ◽  
Minh-Tien Le ◽  
Ngoc-Lu Vu ◽  
Hong-Dang Nguyen ◽  
Van-Tuan Le ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Polarization Vortex

Effect of Additional Shear Strain Layer on Microstructure and Tensile Strength of Fine Wire

2007 ◽  
Vol 340-341 ◽  
pp. 525-530 ◽  
Author(s):  
Satoshi Kajino ◽  
Motoo Asakawa
Keyword(s):  
Tensile Strength ◽  
Surface Layer ◽  
Tensile Test ◽  
Shear Strain ◽  
Crystal Orientation ◽  
Hardened Layer ◽  
High Tensile Strength ◽  
Center Layer ◽  
Fine Wire ◽  
Strain Layer

The mechanical and electrical applications of fine wires (D = 0.1 mm) has become more widely spread. In general, it is well known that fine drawn wires have high tensile strength while maintaining ductility. It has been determined that a hardened layer of around 0.04 mm in depth, referred to as the “additional shear strain layer,” is generated beneath the surface layer of the wire, and this additional shear strain layer affected the tensile strength of the fine wire. As an origin of this phenomenon, it was ascertained that the microstructure of surface layer was finer than that of center layer. The purpose of this paper is to investigate the effect of die angle on the microstructure and the tensile strength of the additional shear strain layer. The tensile test was performed as the surface layer was thinned by electro-polishing, and the crystal orientation and the crystal grain were measured via EBSD. As a result, it was ascertained that die angle affected the tensile strength and crystal grain refinement of the additional shear stray layer.

Joining of polymer and metal tubes by cold forming

2015 ◽  
Vol 231 (6) ◽  
pp. 505-515 ◽  
Author(s):  
LM Alves ◽  
CMA Silva ◽  
PAF Martins
Keyword(s):  
Room Temperature ◽  
Plastic Instability ◽  
Forming Process ◽  
Element Analysis ◽  
Cold Forming ◽  
Structural Bonding ◽  
Hybrid Joints ◽  
Polymer Tube ◽  
Tooling System

This paper proposes a technology for joining polymer and metal tubes by their ends at room temperature, which is an alternative to structural bonding and mechanical couplings. The technology is built upon a two-stage tube forming process in which the metal tube is firstly expanded with a mandrel and, subsequently, assembled and locked by compression beading with the polymer tube by means of localized plastic instability. The presentation provides details on the tooling system and on the experimental and finite element analysis that were carried out during the development of the proposed technology. Special emphasis is placed on establishing the role of process parameters in the joinability of polymer and metal tubes and determining the maximum internal pressure that these hybrid joints are capable to withstand, without leakage.

Formation Mechanisms of ZnO Nanowires: The Crucial Role of Crystal Orientation and Polarity

2013 ◽  
Vol 117 (40) ◽  
pp. 20738-20745 ◽  
Author(s):  
Sophie Guillemin ◽  
Laetitia Rapenne ◽  
Hervé Roussel ◽  
Eirini Sarigiannidou ◽  
Georges Brémond ◽  
...  
Keyword(s):  
Crucial Role ◽  
Crystal Orientation ◽  
Zno Nanowires ◽  
Formation Mechanisms

Onset of the Portevin-Le Chatelier Effect: Role of Synchronization of Dislocations

2014 ◽  
Vol 783-786 ◽  
pp. 198-203 ◽  
Author(s):  
Tatiana Lebedkina ◽  
Nikolay P. Kobelev ◽  
Mikhail Lebyodkin
Keyword(s):  
Flow Stress ◽  
Strain Rate ◽  
Collective Motion ◽  
Rate Sensitivity ◽  
Plastic Instability ◽  
Strain Rate Range ◽  
Dislocation Dynamics ◽  
Transient Kinetics ◽  
Kinetic Measurements

The problem of the onset of the Portevin-Le Chatelier (PLC) effect is revised by combining a study of the kinetics of the flow stress evolution upon abrupt changes in the applied strain rate and acoustic emission (AE) accompanying plastic deformation of an AlMg alloy. The kinetic measurements allow evaluating the strain-rate sensitivity of the flow stress and the time characteristics of transient processes as functions of plastic strain. Using known criteria of plastic instability, domains of instability are constructed in the (strain, strain rate) plane. A particular accent is put on the strain-rate range corresponding to the so-called “inverse” behavior. The comparison of such maps with experimental data on the critical strain testifies to the insufficiency of these criteria for explaining the onset of the PLC effect. Moreover, the slow transient kinetics contradicts observations of the fast development of stress drops. The AE measurements bear witness that the stress serrations are associated with bursts in duration of acoustic events generated by the collective motion of dislocations. The possible role of synchronization of dislocation dynamics on the onset of plastic instability is discussed.

Strain Rate Evolution in Aluminium Alloy Measured by ESPI during Tensile Test

2009 ◽  
Vol 614 ◽  
pp. 155-162 ◽  
Author(s):  
Johann Petit ◽  
Guillaume Montay ◽  
Manuel François
Keyword(s):  
Tensile Test ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Speckle Pattern ◽  
Local Strain ◽  
Plastic Instability ◽  
Electronic Speckle Pattern Interferometry ◽  
The Moment ◽  
The One ◽  
Strain Rate Field

The original and significant achievement of this work is to analyse strain rate field in aluminium alloy sheets during micro tensile test. In-plane Electronic Speckle Pattern Interferometry is used to follow the evolution of the local strain in real time. This paper is based on the detection of the localization on a relatively small area of the analysed specimen: less than 5mm × 4mm area. Moreover the speed of the tensile machine is very low, 0.2 to 0.1µm/s. The phase shifting technique is used to obtain the fringes representative of the material displacement. We can therefore get a very good accuracy in the material displacement. A heterogeneity in strain rate field can be noticed from a deformation stage which doesn’t coincide with the one calculated by the classic Considère’s criterion (dF=0) for the diffuse neck initiation (or plastic instability). We also show, the moment when one of the two slip bands systems becomes predominant, and even only one band continues to exist, this occurring widely before fracture. Finally, the fracture of the specimen occurs across this remaining band. The total strain is measured with a second camera, in white light, and is correlated together with the strain rate field to study the localization.

Sign in / Sign up

Export Citation Format

Share Document