Isothermal and Athermal Transformation of FeNiMo Alloys

Abstract
Kinetic dependence of martensitic transformation and properties changes in Fe-24%Ni-5%Mo alloys with different carbon content have been obtained. Internal friction method was used for the precise investigation of structural changes after austenization, during martensitic transformation at sub zero temperature and during the postheat. The influence : (i) of frequency of oscillations, (ii) rate of cooling and (iii) amplitude of deformation on the time-temperature dependent internal friction during martensitic transformation have been shown. The curves of isothermal decay of austenite have been presented and we have discussed the type and kinetics of martensite transformation, and also the peculiarities of structural formation of martensite. The influence of the composition on the character of phase transformation is connected with the redistribution of interstitials between the dislocations and austenite solid solution before the martensitic transformation at lower temperatures.