| Abstract Scope |
In this study, we present an athermal electro-pulsing treatment (EPT) as a novel field-assisted method to refine the microstructure of high-carbon M50 bearing steel without significant heating. Short, high-density current pulses were applied under near-isothermal conditions. We systematically investigated the effects on phase distribution, grain structure, dislocation dynamics, and nanoscale tribological behavior. EPT above a threshold current density of 140 A/mm˛ produced fine grains and promoted secondary carbide precipitation, while lower intensities induced only recovery or coarsening. The optimized process yielded uniform nano-carbide dispersion and refined grains, significantly enhancing wear resistance. Mechanistic analysis reveals that rapid electronic energy deposition drives non-equilibrium effects of electron wind forces and localized thermal spikes that promote recrystallization and solute redistribution within milliseconds.Athermal EPT achieves outcomes comparable to severe plastic deformation or conventional heat treatments, but without bulk heating, plastic strain, or residual stress. |