Acoustic emission in plastic deformation of metals (review). Report 1

Yudin, A. A.; Иванов, В. И.

doi:10.1007/bf01528739

Cited by 8 publications

(4 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2-4 also show that onsets of macroscopic yielding of alloys tested are asynchronous with the maxima of AE signals appearing in the preyielding period. This phenomenon can be explained with the microplasticity resulting from complex multiaxial loading taking place during channel-die straining [17].…”

Section: Coarse Grained Alloysmentioning

confidence: 99%

Effect of Al alloying on the Hall-Petch strengthening and AE in compressed Mg-Li-Al alloys before and after HPT processing

Pawełek¹,

Ranachowski²,

Piątkowski³

et al. 2011

View full text Add to dashboard Cite

The paper deals with the effect of Al content in two-phase Mg-10Li-xAl (x = 0, 1, 5) alloys on their straining behaviour before and after severe plastic deformation by high pressure torsion. Both coarse-grained and ultrafine-grained alloys were compression strained in channel-die device with simultaneous acoustic emission monitoring. It has been observed that Hall-Petch strengthening in ultra-fine grained alloys superposes with the strengthening resulting from Al alloying (solution hardening, particulate strengthening). Superposition of these strengthening mechanisms becomes stronger with increase in Al content, presumably due to enhanced grain refining effect.

show abstract

Section: Coarse Grained Alloysmentioning

confidence: 99%

Effect of Al alloying on the Hall-Petch strengthening and AE in compressed Mg-Li-Al alloys before and after HPT processing

Pawełek¹,

Ranachowski²,

Piątkowski³

et al. 2011

View full text Add to dashboard Cite

show abstract

“…It is mentioned in [1] that the study of the signal spectrum of acoustic emission can be important both theoretically (to estimate the duration of action of the AE sources, to analyze their precise time structure) and practically (to separate the contributions of strain and fracture in an acoustic emission, to separate useful signals from extraneous signals).…”

mentioning

confidence: 99%

“…The most important factor for spectral-data analysis is the relationship between effective extension F ef of the spectral density of a mechanical-stress pulse, that is, the spectral density's limiting frequency and the duration (lifetime) of this pulse τ [1]:…”

mentioning

confidence: 99%

Use of Spectral-Correlation Analysis in Acoustic-Emission Inspection of Pig Launchers-Receivers of Oil Main Pipelines

Kuleshov

Lapshin

Oglezneva

2005

Russ J Nondestruct Test

View full text Add to dashboard Cite

The possibilities of using characteristics of special-correlation analysis as informative parameters for the acoustic-emission (AE) inspection of pig launchers-receivers (PLRs) of oil main pipelines (OMPs) are considered. The acoustic emission caused by wind and atmospheric precipitation that act on a pipe and, thus, generate noise are studied. It can be concluded from the preliminary analysis that the effective width and median frequency of a spectrum can be used to identify the AE inspection processes of PLRs of OMPs.The specific character of an object selected for AE inspection is determined by placing a pig launcherreceiver (PLR) of an oil main pipeline (OMPs) in open air, thus exposing it to the action of natural phenomena (precipitation, wind), which can disguise a genuine AE signal with noise. Consequently, to ensure that the aforementioned noise is identified, the problem of AE inspection involves selection of an informative parameter of the AE signal. Let us consider the usefulness of spectral-correlation analysis as it relates to this purpose.It is mentioned in [1] that the study of the signal spectrum of acoustic emission can be important both theoretically (to estimate the duration of action of the AE sources, to analyze their precise time structure) and practically (to separate the contributions of strain and fracture in an acoustic emission, to separate useful signals from extraneous signals).The most important factor for spectral-data analysis is the relationship between effective extension F ef of the spectral density of a mechanical-stress pulse, that is, the spectral density's limiting frequency and the duration (lifetime) of this pulse τ [1]:This fact was pointed out first for acoustic emission by Stephens and Pollock, who had taken the shape of the pulse to be Gaussian. The effective width of the correlation function of the AE pulse is determined also by τ [2].The autocorrelation function is a time characteristic of a signal that represents the rate of signal variation in time and the signal duration without expanding the signal into harmonic components. Microdeformation and microfracture have discrete time kinetics as a result of their joint action. Any joint action that causes damage to a material (avalanching of dislocations, merging of cracks with one other or with a macrocrack, etc.) is accompanied by a primary elastic pulse, whose radiation process is an AE act itself [3]. The duration of this pulse can be obtained from the autocorrelation function by considering the calculated autocorrelation interval. Thus, it can be assumed that the durations of a real AE act and noises differ and the former can be taken as the classification parameter.The most comprehensive data on AE spectra were obtained by Hatano [4], who used narrowband detection with five resonance transducers characterized by frequencies of 0.1, 0.4, 1, 2, and 4 MHz. His studies were performed on industrial-grade polycrystalline aluminum and are summarized as follows. The spectrum is enriched with high-frequency components as d...

show abstract

“…The investigations of plastic deformation and fracture processes in metals and the inspection of the material structural state involve an extensive use of the acoustic emission (AE) method [8][9][10][11]. This is due to the fact that AE signals are generated in almost all physical processes that occur in a material under loading.…”

mentioning

confidence: 99%

Acoustic emission in hafnium under tensile deformation

et al. 2011

View full text Add to dashboard Cite

The paper addresses the dependence of acoustic emission produced in rolled hafnium GFÉ-1 under tensile deformation on the material's structural state. A correlation has been established between the material structure, the level of mechanical properties and the values of acoustic parameters. Acoustic emission in non-recrystallized hafnium under tensile deformation is recorded only at the stages that precede fracture. Upon recrystallization annealing at temperatures of 1123 and 1373 K acoustic emission occurs at all the stages of tensile deformation. The highest level of acoustic emission activity in hafnium is observed during the transition from elastic to elastic-plastic strain.Introduction. Nowadays, hafnium is widely used in control rods for nuclear reactors, in neutron-absorbing containers, in developing special alloys [1-3]. Its successful use and extension of the range of its applications call for further investigation of the influence of structural factors on the physical-mechanical properties of the material.Numerous research efforts undertaken recently [4][5][6][7] have been focused on a study of the mechanisms of plastic deformation in hafnium depending on the structural state and test conditions. The investigations of plastic deformation and fracture processes in metals and the inspection of the material structural state involve an extensive use of the acoustic emission (AE) method [8][9][10][11]. This is due to the fact that AE signals are generated in almost all physical processes that occur in a material under loading. In this connection, it is of great interest is to study AE in metallic materials in various structural states, namely: upon deformation treatment and recrystallization. Earlier AE investigations [12][13][14] were performed on zirconium and titanium -the metals with the same face-centered close-packed lattice as in hafnium. However, scant attention was given there to the state of microstructure in the materials studied. We have found no publications on the AE investigation of hafnium and related alloys.The objective of the present work is to study AE in rolled hafnium of grade GFÉ-1 depending on the structural state of the material in the process of tensile loading.Experimental. The investigation was performed on hafnium GFÉ-1 produced by the calcium-thermal reduction method. Hafnium was electron-beam-melted to make an ingot. The ingot was hot-forged to a slab which in turn was rolled to produce a 5-mm-thick strip. Upon recrystallization annealing, the strip was rolled at 673 K to prepare a 2.2-mm-thick sheet, which corresponds to the 56% deformation. Specimens of 2 2 4 . × mm cross section and initial gauge length of 27 mm for tensile tests with simultaneous recording of AE signals were spark-cut from the sheet along the direction of rolling. The tests were carried out using a Mod. U10-1 universal testing machine, with a deformation rate of 1 10 3 ⋅ − s −1 at room temperature. During the tensile loading of the specimens, the deformation and

show abstract

Acoustic emission in plastic deformation of metals (review). Report 1

Cited by 8 publications

References 26 publications

Effect of Al alloying on the Hall-Petch strengthening and AE in compressed Mg-Li-Al alloys before and after HPT processing

Effect of Al alloying on the Hall-Petch strengthening and AE in compressed Mg-Li-Al alloys before and after HPT processing

Use of Spectral-Correlation Analysis in Acoustic-Emission Inspection of Pig Launchers-Receivers of Oil Main Pipelines

Acoustic emission in hafnium under tensile deformation

Contact Info

Product

Resources

About