Application of Magnetoacoustic Emission Technique to Temper Embrittlement Characterization of HY-80 Steel

Abstract

Our previous work has shown that magnetoacoustic emission (MAE) is mainly contributed by the motion of 90° domain walls which lags behind that of 180° domain walls in phase [1]. The amplitude of MAE burst is always higher in the embrittled samples than in unembrittled one for a sufficient level of internal magnetic field. It has been also shown that for a small internal magnetic field, the MAE activity is higher in an unembrittled sample than is in embrittled ones. This is a direct evidence of the effect of potential barriers at the grain boundaries that determine the amplitude of the MAE burst under given conditions [2]. The pulse height analysis of the MAE spectral pattern has been included in our more recent work (3]. The results have shown that the Gaussian- like distribution broadens upon the decrease in impact strength of HY-80 steel samples due to embrittlement up to a certain level.