Emisja akustyczna w materiałach ceramicznych i kompozytach metalicznych poddanych próbie ściskania - badania wstępne

There are presented, at the first time, the results of the preliminary investigations of the correlations between the behaviour of acoustic emission (AE) and both the channel-die and the standard compression deformation processes occurring in ceramic and composite materials at ambient temperature. The obtained results are preliminarily discussed in the context of possible deformation mechanisms as well as in the context of structural observations by using the optical microscopy. In the case of the ceramics (cordierite - mullite) the large range of high rate of the AE events has been observed at the final stage of the compression test. The most probably it is due to the so-called pseudoplasticity effect related with the increase of porosity and the development of cracking processes with the increasing internal stresses. In the case of the composites - Mg-4Li-5Al and Mg-4Li-3Al alloys reinforced by delta. Al2O3 fibres - it has been observed different AE behaviour. The high AE activity is observed rather at the onset of deformation process and its range is more longer in time for the material of greater contents of A However, the general character of the peaks of the rate of AE is similar, and the most probably it is related mainly with the mechanisms of the cracking of the .delta. Al2O3 fibres.