A nanocrystalline grain oriented silicon steel prepared by severe plastic deformation

Abstract

A nanocrystalline electric steel foil with (1 1 0) preferred orientation was produced by severe plastic deformation (SPD) of as-quenched Fe–3.18 wt.% Si alloy followed by a recrystallization annealing at 500 °C for 30 min. Austenite (γ) to lath-like martensite (LM) transformation occurs in the alloy when quenched from a temperature of 1150 °C by a rapid spraying flow of ice brine. LM is uniformly distributed with low dislocation density and average pocket size of 150 nm. SPD of lathy structure results in a heavily deformed structure with average subgrain size of 18–25 nm and high-density dislocation cell, which is relaxed with the subsequent recrystallization and evolves a nanocrystalline phase with an average size of 21–25 nm during the recrystallization annealing. The initially dominant (1 1 0) orientation in the hot-rolled alloy survives in quench and cold deformation and is intensified in recrystallization annealing.