Acoustic emission during phase transformations in alloys

Voronenko, B. I.

doi:10.1007/bf00769364

Cited by 11 publications

(2 citation statements)

References 28 publications

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“…80 Further research in this area is necessary to strengthen our understanding of these physical mechanisms. Similarly, the mechanism of AE generated during phase transformations such as martensitic transformation is caused by the rapid variation in the shape of deforming volume, 81 however, diffusional transformation of phases is less understood.…”

Section: Introductionmentioning

confidence: 99%

Indentation testing and its acoustic emission response: applications and emerging trends

Faisal

Ahmed

Reuben

2011

International Materials Reviews

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This review summarises the state of knowledge on acoustic emission (AE) techniques applied to material property evaluation during indentation (e.g. hardness) testing. There are two aspects of application of AE technique to indentation which makes it unique, i.e. (1) enhancing the understanding of the evolution of material accommodation mechanisms under loading and (2) qualitative and quantitative evaluation of mechanical properties such as fracture toughness and bond strength from the AE signal. Both of these aspects have the potential to improve our understanding of the structure property relationships of current and future generation materials. In addition, the knowledge developed here can be incorporated to improve the AE based condition monitoring systems for stress critical applications. This review concentrates on the phenomena which occur during indentation and how its examination can be used to study more fundamental behaviour of materials such as deformation and fracture. The uncertainty in quantifying and measuring the total crack surface in indentation makes a simple fracture mechanics based assessment of toughness difficult. It is therefore expected that correlation between AE and fracture patterns will lead to an improved method for material's quality evaluation. The main part of this review is presented on AE of material classifications. These classifications include ceramics, glasses, composites, metals and metallic foams, thin solid films and thermally sprayed coatings. Apart from quasi-static indentation testing, attention has also been paid to studies on various AE instrumented indentation systems so that information can be derived about the progress of deformation and cracking processes. This review discusses the studies summarising those aspects that have so far been established and the areas of controversy and/or lack of knowledge. The prospect of using AE techniques to monitor indentation tests is also assessed, taking into account those few studies that have been reported so far in different groups of materials. Although with some limitations, it is concluded that AE monitored indentation testing has considerable scope to assess in much more detail the deformation and cracking properties of materials under localised stress condition. It is possible to construct empirical relationships and develop theoretical understanding linking mechanical parameters with AE signal characteristics and its derived features. However, the occurrence of multiple events at different locations superimposing the AE signal requires more advanced signal processing techniques. With the advancement of very thin films and nanomaterials, it is anticipated that AE response measured during nanoindentation will be critical for enhancing our understanding of future generation applications, as it allows individual events to be investigated without resorting to more complex signal processing techniques. In terms of material accommodation, the understanding of physical mechanisms generating AE require a multiscale approach, e...

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Section: Introductionmentioning

confidence: 99%

Indentation testing and its acoustic emission response: applications and emerging trends

Faisal

Ahmed

Reuben

2011

International Materials Reviews

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“…During phase transformations, acoustic effects are generated as a result of dynamic triggering of cumulated energy. Due to the non-invasive method of measuring acoustic emission, it is possible to monitor transformation processes in steel [8][9][10][11]. As a result of changes in the tested object, elastic waves are propagated.…”

Section: Introductionmentioning

confidence: 99%

Bulletin of the Polish Academy of Sciences: Technical Sciences

Trafarski,

Łazarska,

Ranachowski

2021

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of acoustic emission during heat treatment processes show that this method is the source of relevant information about the phenomena occurring in the processed material [6,7,11,12]. Measurement of acoustic emission signals is performed using the passive method. The apparatus used has no influence on the tested object. Registered signals are related only to the acoustic effects occurring in the material under study [13]. Sources of acoustic emission in metals are [3,5,[14][15][16][17][18][19][20][21]: dislocation motion due to plastic deformation, formation of twins, phase transitions of the displacive type, micro and macro cracks. Acoustic emission is a method of obtaining new information about phenomena occurring during phase changes. The applied research techniques may be used in the industry to test large samples in the future. Monitoring of heat treatment processes is vitally important for the utility values of finished industrial products. By tracking the breakdown kinetics of supercooled austenite, processes can be regulated and improved. New solutions and technologies in this aspect are still being searched for. MATERIALS AND METHODS Research materialThe samples were prepared from 27MnCrB5-2 steel. Samples were taken and prepared from one steel rod. Cylindrical specimens with diameters of 22 mm and height of 25 mm were made. The chemical composition of 27MnCrB5-2 steel is presented in Table 1.The steel subjected to the tests is used in the automotive industry for fasteners of machine parts. The fasteners are heat treated to improve the properties of the material from which they are made. During the tests, the continuous cooling process was performed on the samples.

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Acoustic emission produced by the delta-to-alpha phase transformation in Pu-Ga alloys

Heiple

Carpenter

1992

Metall Trans A

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Acoustic emission during phase transformations in alloys

Cited by 11 publications

References 28 publications

Indentation testing and its acoustic emission response: applications and emerging trends

Indentation testing and its acoustic emission response: applications and emerging trends

Bulletin of the Polish Academy of Sciences: Technical Sciences

Acoustic emission produced by the delta-to-alpha phase transformation in Pu-Ga alloys

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