THE INTERNAL FRICTION OF THE PEARLITIC BAINITIC AND MARTENSITIC TRANSFO-RMATIONS IN Fe-Ni-C ALLOYS
Fe-Ni-C合金中珠光体、贝氏体及马氏体的相变内耗

The low frequency internal friction of the pearlitic,bainiticand martensitic transformations in three Fe-Ni-C alloys has been studied.Theresults show that the internal friction of the martensitic transformation is incorrespondence with the model based on the hysteresis loss mechanism associ-ated with stress-induced motion of the interface dislocation,while that of thepearlitic and bainitic transformations does not obey this model.At a constantfrequency,the internal friction peaks of the pearlitic and bainitic transforma-tions increase as the cooling rate increases, but the temperature of the internalfriction peaks decreases,and the (?) is directly proportional to the (?)/f_mT_m.When the frequency increases,the (?) of the pearlitic and bainitic transfor-mations lowers apparently,and the temperature of the damping peaks increases.It was revealed that,at the begining of the pearlitic and bainitic transforma-tions under continuous cooling,there is no lattice softening.The internal fric-tion of the isothermal bainitic transformation in a Fe-Ni-C alloy has alsobeen studied,which proves that there appears a damping peak in the incubationperiod,and the damping peak may be attributed to the nucleation ofbainite.Consequently it infers that the mechanism of the bainite reaction seemssimilar to that of pearlite.