99
Texture development in Nd-Fe-V alloys by hot deformation in view of
permanent magnet properties
I.Popa
1,2,a
, S. Rivoirard
1,b
, D. Chateigner
3,c
, T. Hansen
4,d
, D. Fruchart
2,e
1
CNRS-CRETA, BP 166, 38042 Grenoble cedex 9, France
2
CNRS-Laboratoire de Cristallographie, BP 166, 38042 Grenoble cedex 9, France
3
CRISMAT-ENSICAEN, 6, boulevard du Maréchal Juin, 14 050 Caen, France
4
Institut Laue Langevin, 6 Rue J. Horowitz, BP 156, 38042 Grenoble, cedex 9, France
a
ioana.popa@esrf.fr,
b
sophie.rivoirard@grenoble.cnrs.fr,
c
daniel.chateigner@ismra.fr,
d
hansen@ill.fr,
e
daniel.fruchart@grenoble.cnrs.fr
Keywords: permanent magnet, high-speed hot forging, initial microstructure, intergranular phase
content, texture
Abstract.
In this study, a hot forging process is applied to Nd-Fe-V as cast alloys in order to develop
both the microstructure and the crystallographic texture appropriate for permanent magnet
properties. A neutron diffraction texture analysis is used to account for the extrinsic magnetic
anisotropy: the stabilisation of the Nd(Fe,V)
12
hard magnetic phase has been achieved during
forging but its extrinsic anisotropy level remains low. Attempts to understand this phenomenon are
made through a discussion on the Nd-Fe-V alloy rheological and mechanical behaviour and a
comparison with Nd-Fe-B permanent magnets.
Introduction
Good levels of coercivity and enhanced magnetic anisotropy are the key for high
performance magnets. In the field of rare earth - transition metal alloys, the development of
anisotropic powders is needed for bonded magnet applications. Anisotropic Nd-Fe-B based alloys
are already commercially available whereas, only recently some studies report on Nd-Fe-V-N alloys
with potential permanent magnet properties.
The NdFe
10.5
V
1.5
compounds, one of the 1:12 phases RFe
12-X
M
X
(R = rare earth, M =
transition metal), can be considered as potential materials for permanent bonded magnets because of
their high intrinsic magnetic properties, higher than those of the Nd
2
Fe
14
B-type materials [1], which
are presently the most used as permanent magnets. For this purpose, good extrinsic magnetic
properties are also needed: coercivity, and extrinsic magnetic anisotropy. Up to now, mechanical
alloying enabled to obtain a high coercivity in this type of materials (H
c
= 872.17 kA/m) [2].
Materials Science Forum Vols. 495-497 (2005) pp. 1389-1394
online at http://www.scientific.net
© 2005 Trans Tech Publications, Switzerland
Licensed to Daniel Chateigner (daniel.chateigner@ismra.fr) - ISMRA - France
All rights reserved. No part of the contents of this paper may be reproduced or transmitted in any form or by any means without the
written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net . (ID: 195.83.126.10-28/04/05,14:14:49)