Acoustic emission from moving dislocations

Kiesewetter, N.

doi:10.1016/0036-9748(74)90247-6

Cited by 13 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This can be regarded as a periodic process, if we assume, that every dislocation moves in the same way as the preceding one. By Fourier analysis the movement of the dislocations may be presented as a sum of harmonic oscillations [ 5 ] . I n order to simplify the problem, we wish to consider the first harmonic only.…”

Section: Discussionmentioning

confidence: 99%

The acoustic emission from moving dislocations in aluminium

Kiesewetter

Schiller²

1976

Phys. Stat. Sol. (a)

View full text Add to dashboard Cite

The acoustic emission during tensile tests is investigated for several types of aluminium alloys. It. is found that the mean square amplitude of the continuous emission is proportional to strain rate and sample length. It is assumed that the continuous emission is generated by dislocation loops, which are created continuously a t Frank-Read sources. According to this model the mean square amplitude of the continuous emission U8 is proportional to the total length of the mobile dislocations L and the size of the loops I : vz -LZ. Information about I was taken from Kuhlmann and Wilsdorf's observations of slip lines a t the surface of deformed aluminium single crystals.An mehreren Aluminiumlegierungen wird die Schallemission wiihrend plastischer Verformung untersucht. Es wird gefunden, daB das mittlere Amplitudenquadrat der kontinuierlichen Emission der Verformungsgeschwindigkeit und der Probenliinge proportional ist.Es wird angenommen, daD die kontinuierliche Emission von Versetzungen herriihrt, die gleichmiiBig von Frank-Read-Quellen ausgestoBen werden. In diesem Modell ist das mittlere Amplitudenquadrat der Emission der gesamten beweglichen Versetzungsliinge L und der LLnge I der Versetzungsschleifen proportional : 6 -LZ. Die Ergebnisse werden mit Werten der Gleitlinienlangen auf Einkristallen von Kuhlmann und Wilsdorf verglichen.

show abstract

Section: Discussionmentioning

confidence: 99%

The acoustic emission from moving dislocations in aluminium

Kiesewetter

Schiller²

1976

Phys. Stat. Sol. (a)

View full text Add to dashboard Cite

show abstract

“…The greatest part of that power is dissipated as heat, while the rest can still be considered as a source for continuous acoustic emissions irradiated during plastic flow in metals. Despite the considerable differences in the approaches used in numerous early attempts to rationalise the AE behaviour in terms of the dislocation behaviour [14][15][16][17][18], many models converge in claiming that the AE energy emitted by moving dislocations is proportional to the density of mobile dislocations and their mean free path Λ…”

mentioning

confidence: 99%

Phenomenological approach towards modelling the acoustic emission due to plastic deformation in metals

2019

View full text Add to dashboard Cite

Considering acoustic emission (AE) as a phenomenon reflecting the elastic energy dissipation process in deforming metals, a simple yet self-consistent model is proposed to account for the AE behaviour accompanying microstructure evolution during uniform plastic deformation of metals. The relationship between the AE power, mobile dislocation density and plastic flow characteristic parameters -the strain hardening rate and flow stress -is derived and experimentally verified for face centred cubic metals with different stacking fault energies (SFE). Despite its simplicity, the proposed purely phenomenological relation captures most of the salient features of the AE behaviour of early deformation stages in metals.

show abstract

“…AE accompanies many irreversible processes occurring in plastically deforming solids, including dislocation motion, mechanical twinning, stress-or strain-induced phase transformations and cracking. [1][2][3][4][5][6][7][8] The AE technique has been recognised to be highly sensitive to dislocation dynamics since the very first work by J. Kaiser (dated back to 1950 9) ) followed by Fisher and Lally 10) who were the first to relate the AE bursts to the intermittent dislocation motion. Then Tetelman, Gillis, Pollock, James and Carpenter, Mallen and Bolin, Ono, Kishi et al 3,[11][12][13][14][15][16][17][18][19] pioneered the fundamental studies on the AE behaviour in plastically deforming metals and engineering alloys, circa in 1970s.…”

Section: Background and Motivationmentioning

confidence: 99%

“…The experimentally obtained AE parameters, such as AE power and the median frequency of the spectral density, can be linked to the development of the defect microstructure under increasing load. Drawing inspiration from the concepts articulated by the AE pioneers in the 70th of the past century, 2,3,11,16,37,38) we treat AE as a result of fluctuating intermittent dislocation motion, generating the continuous random Ornstein-Uhlenbeck process in accordance with eq. ( 3).…”

Section: A Brief Overview Of the Modelmentioning

confidence: 99%

Towards Predicting Necking Instability in Metals by Acoustic Emission Model Analysis

Vinogradov,

Danyuk,

Yasnikov

2024

Mater. Trans.

View full text Add to dashboard Cite

We have enhanced a basic single-variable dislocation evolution modelling framework to encompass the acoustic emission (AE) characteristics observed in metals and alloys during the homogeneous strain hardening stage up to the point of macroscopic necking instability under tensile stress. To validate our proposed modelling approach, we conducted comprehensive experiments using pure Ag, Cu, Al, and Ni, representing fcc metals with stacking fault energies increasing in the listed order of materials. Our model successfully captures both previously established and newly discovered patterns in the evolution of the AE spectral density. A key focus of this research is to demonstrate the ability to directly derive the critical parameter that governs the evolution of dislocations and, consequently, overall strain hardening, namely the rate of dynamic dislocation recovery, directly from AE measurements. As a prime result, we can predict the conditions leading to necking, specifically the necking strain, well in advance solely from AE data.

show abstract

Acoustic emission from moving dislocations

Cited by 13 publications

References 0 publications

The acoustic emission from moving dislocations in aluminium

The acoustic emission from moving dislocations in aluminium

Phenomenological approach towards modelling the acoustic emission due to plastic deformation in metals

Towards Predicting Necking Instability in Metals by Acoustic Emission Model Analysis

Contact Info

Product

Resources

About