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

Tatiana Lebedkina; Nikolay P. Kobelev; Mikhail Lebyodkin

doi:10.4028/www.scientific.net/MSF.783-786.198

Paper Titles

Isothermal and Non-Isothermal Annealing of Cold-Rolled Al-Mn-Fe-Si Alloys with Different Microchemistry States
p.174

Effect of Heat Treatment Conditions and Small Addition of Cu on Occurrence of Serration in Al-Si Alloys
p.180

Separation of Pure Silicon from Al-Si Alloy Melts
p.186

The Evolution of Texture and Deformation Anisotropy at an Equal Channel Extruded Aluminum 1050 Alloy
p.192

Onset of the Portevin-Le Chatelier Effect: Role of Synchronization of Dislocations
p.198

Multiscale Analysis of Acoustic Emission during Plastic Flow of Al and Mg Alloys: From Microseconds to Minutes
p.204

Quantitative Investigation on Nano-Scale Precipitates in an Al-7.5Zn-1.7Mg-1.4Cu-0.12Zr Alloy under Various Aging Tempers
p.210

Plating on Developed Al-Mg-Zn Alloy Casting and its Glossiness
p.216

Statistical and Physical Micro-Feature-Based Segmentation of Cortical Bone Images Using Artificial Intelligence
p.222

HomeMaterials Science ForumMaterials Science Forum Vols. 783-786Onset of the Portevin-Le Chatelier Effect: Role of...

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

Abstract:

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.