Iakovlev V. Effect of cyclic martensitic transformation on the diffusion processes and the decay of carbon a-solid solution in iron-based alloys

Cyclic martensitic transformation influence on the diffusion processes in the metastable iron-based alloys in the defects in the crystal structure formation was investigated in this work. It was shown that the diffusion of a substitutional and interstitial atoms (carbon) as a result of cyclic martensitic transformations accelerated with accumulation of internal stresses and crystal structure defects. Significant acceleration of the diffusion mobility of atoms as a result of cyclic martensite transformations performed by the impact of two independent mechanisms - athermal and thermally activated. First mechanism implemented as a result of the shift character of the direct and reverse transformations under the lattice rebuilding. The second one was realized under the process of diffusion annealing of hardened alloy. A significant increase in the diffusion mobility of carbon atoms under the cyclic martensitic transformations resulted to the acceleration of carbon a-solid solution dissolution. Consequently, a speed of two-phase and single-phase dissolution of a-solid solution increased substantially under the low-temperature annealing (100 ° C) of phase-hardened martensite of 60N25 steel.