Archives of Acoustics, 32, 4, pp. 955-962, 2007

Acoustic emission and the Portevin-Le Châtelier effect in tensile tested Al alloys processed by ARB technique

Andrzej PAWEŁEK
Aleksander Krupkowski Institute of Metallurgy and Materials Science Polish Academy of Sciences

Jan KUŚNIERZ
Aleksander Krupkowski Institute of Metallurgy and Materials Science Polish Academy of Sciences

Joanna BOGUCKA
Aleksander Krupkowski Institute of Metallurgy and Materials Science Polish Academy of Sciences

Zdzisław JASIEŃSKI
Aleksander Krupkowski Institute of Metallurgy and Materials Science Polish Academy of Sciences

Zbigniew RANACHOWSKI
Institute of Fundamental Technological Research Department of Physical Acoustics Polish Academy of Sciences

Przemysław RANACHOWSKI
Institute of Fundamental Technological Research Department of Physical Acoustics Polish Academy of Sciences

Feliks REJMUND
Institute of Fundamental Technological Research Department of Physical Acoustics Polish Academy of Sciences

Tomasz DĘBOWSKI
Institute of Fundamental Technological Research Department of Physical Acoustics Polish Academy of Sciences

The paper presents the investigations of the relation between the acoustic emission (AE) and the Portevin-Le Châtelier (PL) phenomena occurring in tensile tested two kinds of aluminium alloys: not-predeformed and predeformed earlier using the technique of accumulative rolling banding (ARB). There have been found essential correlations between AE and PL effects in ARB not-predeformed alloys. The tensile tests for ARB predeformed alloys were performed on a series of samples of various degree of work hardening and it has been observed that the correlations between the AE and PL effects are not so pronounced as in the case of ARB not-predeformed alloys. The results of AE measurements obtained using a new software allowed additionally to carry out the spectral analysis of AE signals and, in consequence, to determine the acoustic maps (acoustograms) and the spectral characteristics which are very useful in the discussion of the relations between the non-homogeneous strain mechanisms of the PL effect and the mechanisms of AE events generation. The results are discussed in the context of the existing dislocation models of the PL effect and the theoretical concepts of AE sources.
Keywords: acoustic emission (AE), Portevin-Le Châtelier (PL) effect, tensile test, dislocations, strain mechanism, nanocrystalline and/or ultra fine-grained structure, accumulative roll-bonding (ARB)
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