The hysteresis loops as well as the spin distributions of Sm-Co/α-Fe bilayers have been investigated by both threedimensional (3D) and one-dimensional (1D) micromagnetic calculations, focusing on the effect of the interface exchange coupling under various soft layer thicknesses t s . The exchange coupling coefficient A hs between the hard and soft layers varies from 1.8 × 10 −6 erg/cm to 0.45 × 10 −6 erg/cm, while the soft layer thickness increases from 2 nm to 10 nm. As the exchange coupling decreases, the squareness of the loop gradually deteriorates, both pinning and coercive fields rise up monotonically, and the nucleation field goes down. On the other hand, an increment of the soft layer thickness leads to a significant drop of the nucleation field, the deterioration of the hysteresis loop squareness, and an increase of the remanence. The simulated loops based on the 3D and 1D methods are consistent with each other and in good agreement with the measured loops for Sm-Co/α-Fe multilayers.

The effects of rare earth (RE) on the microstructure and mechanical properties of a pearlitic steel wire rod have been investigated under the dual low‐oxygen condition. The results show that the wire rods with different RE contents all have pearlite microstructure. As RE content increases from 0 to 310 ppm, the pearlite substructures such as interlamellar spacing, pearlite colony size and ferrite grain size decreasing remarkably, indicating that the nucleation and growth behavior of pearlite have changed. This is attributed to the combined effects of stimulating nucleation by large number of micrometer scale RE‐containing inclusions and decreased carbon diffusion due to RE in solution. As a results, the changes in microstructure lead to simultaneous enhancement of strength, plasticity, impact toughness and microhardness of pearlite wire rod, demonstrating that adding appropriate content of RE under the dual low‐oxygen condition is an effective alloying method to optimize the microstructure and mechanical properties of pearlitic steel wire rod.This article is protected by copyright. All rights reserved.