Structure and magnetic properties of Fe-Nb-B amorphous/nanocrystalline alloys produced by compaction of mechanically alloyed powders
|Jhon J. Ipus 1, Javier S. Blazquez 1, Victorino Franco 1, Alejandro Conde 1, Marek Krasnowski 2, Tadeusz Kulik 2, Sergio Lozano-Perez 3|
1. Universidad de Sevilla (USE), Sevilla 41012, Spain
Compaction of Fe85Nb5B10 and Fe75Nb10B15 powders obtained by mechanical alloying in a Spex mill was performed under isostatic conditions at 7.7 GPa at different temperatures (823, 973 and 1273 K). Quality of compaction, microstructure, thermal stability and magnetic properties were studied using different techniques: scanning and transmission electron microscopy, X-ray diffraction, differential scanning calorimetry and vibrating sample magnetometry. The as-milled powder of the alloy with 5 at. % Nb exhibits two phases: bcc‑Fe(Nb,B) nanocrystals (~10 nm) and almost pure B inclusions (~100 nm). However, in the case of the alloy with 10 at. % Nb, an amorphous phase is also observed. The presence of this phase enhances the quality of compaction. Compaction at 823 K preserves both microstructure and magnetic properties of the as-milled powder in both alloys. Compaction at 973 K affects mainly the crystalline fraction of the alloy with 10 at. % Nb. Compaction at 1073 K yields the formation of bcc-Nb and fcc-Fe23B6 type crystals which magnetically harden the material.
Presentation: Poster at E-MRS Fall Meeting 2009, Symposium H, by Javier S. Blazquez
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-25 13:05 Revised: 2009-06-07 00:48