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Electropulsing at room temperature was applied to a medium carbon low alloy steel 30CrMo with varying peak voltage and current. The results showed that the pearlite colony in the specimen treated with electropulsing was smaller than that without electropulsing treatment. It was found that the lamellar structure of pearlite was refined. The grain refinement of pearlite was more obvious when the applied electric current density was higher. This may be attributed to additional free energy for the nucleation of pearlite provided by electropulsing and/or the enhancement of dislocation movement caused by electropulsing.

The thermal stability of Nb–Cr–Mo alloy with the composition Nb-22.5Cr-2.5Mo (at.%), was studied by thermal exposure experiments in vacuum conditions at 1200 °C for 30 h, 50 h, and 100 h. The phase composition consists of Nb and C15 NbCr2, and the vast majority of alloying element Mo is found in the Nb matrix not in NbCr2 particles. The grain size of Nb matrix exhibits a certain degree of growth during the thermal exposure process, while the grain size of NbCr2 has no obvious change due to its high thermal stability. After thermal exposure at 1200 °C for 100 h, the alloy keeps its higher strength by the solid solution strengthening effect of Mo and the dispersion strengthening of NbCr2 particles. At the same time, it has good plasticity due to dislocation slip in the Nb matrix and the emergence of stacking faults, twins and partial dislocations in NbCr2 particles.

The application of electropulse to hot-rolled and cold-rolled, medium carbon low alloy steels has generated completely different effects. For cold-rolled steel samples, electropulsing treatment causes microstructure refinement and, hence, increments in tensile strength, yield strength, and elongation. For hot-rolled steels, the effect of electropulsing is found to be negligible. This proves the importance of dislocations in the micromechanism of electropulse-induced microstructure transformation in solids. The optimal electropulse parameters for the improvement of cold-rolled steels are observed. The experimental observations are explained within the frameworks of thermodynamics and kinetics of microstructure transformation.