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2001
Journal Article
Titel
Acoustic fields in a steel single crystal in austenitic and martensitic states
Abstract
The method of laser interferometry was used to study the distribution of acoustic fields, symmetry and area of ultrasonic beam, and local patterns of the fields of elastic distortions in 60N21 steel taken in different structural states (austenitic single crystal, martensitic pseudosingle crystal, and austenitic polycrystal). The character of the acoustic-field distribution in the martensitic state was shown to reflect the growth cells of the initial austenitic crystal. The dependence of the wave velocity on the magnetic-field strength is nonmonotonic, whereas in austenitic polycrystalline state, the velocity monotonically changes with increasing magnetic field, with no saturation observed in the fields of up to 22 kOe. Such a dependence is caused by the magnetization of superparamagnetic austenite. The attenuation factor of austenite polycrystal contains a component contributed by carbides.