Micostructure and Magnetic Properties in Nanostructured Fe and Fe-Based Intermetallics Produced by High-Pressure Torsion

Abstract

The microstructure and magnetic properties of nanostructured pure iron, FeCo and FeNi₃ produced by high-pressure torsion (HPT) were investigated. Electron backscattered diffraction (EBSD) technique was used to study the evolutions in microstructure and crystallographic texture during HPT, revealing that a weak deformation texture with an orientation of < 110> _bcc being parallel to the disc normal for pure iron and FeCo while < 110> _fcc was found to be parallel to the hoop direction of the HPT disc in FeNi₃. The grain size of the HPTed materials was characterized by means of EBSD and transmission electron microscopy (TEM), and its influence on the coercivity was investigated. The other highlight of this paper is the use of a focused ion beam (FIB)-SEM dual beam instrument. This enabled us to obtain quite high image quality (IQ) values for the EBSD measurements even for the highly deformed microstructure in the current ferromagnetic intermetallics.