Internal Friction Study of the Influence of Deep Cryogenic Treatment on the Microstructure of a Bainitic Steel

Abstract

The influence of deep cryogenic treatment (DCT) on the microstructure of a bainitic steel is investigated by means of internal friction and transmission electron microscopy (TEM). Two relaxation peaks (Pc1and Pc2) are observed during cooling and one relaxation peak (Ph) during heating from 100 to 320K. Peak Pc1may be related to dislocation pinning. Peak Phis attributed to dislocation-carbon atoms interaction. The decreasing of peak Phafter cycles deep cryogenic cooling indicates that soaking time under the deep cryogenic temperature is not contributed to the precipitation of carbides, while the cycles cryogenic treatment lead to more fine carbides precipitation.