Optimization of the magnetic properties of FePd alloys by severe plastic deformation

Abdelahad Chbihi (1) , Xavier Sauvage (1) , Cécile Genevois (1) , Didier Blavette (1) , Dmitry Gunderov (2) , Alexander Popov (3)

1 GPM - Groupe de physique des matériaux
2 IPAM - Institute for Physics of Advanced Materials
3 IMP - M.N. Mikheev Institute of Metal Physics

A FePd alloy was nanostructured by severe plastic deformation following two different routes: ordered and disordered states were processed by high pressure torsion (HPT). A grain size in a range of 50 to 150 nm is obtained in both cases. Severe plastic deformation induces some significant disordering of the long range ordered L10 phase. However, Transmission Electron Microscopy (TEM) data clearly show that few ordered nanocrystals remain in the deformed state. The deformed materials were annealed to achieve nanostructured long range ordered alloys. The transformation proceeds via a first order transition characterized by the nucleation of numerous ordered domains along grain boundaries. The influence of the annealing conditions (temperature and time) on the coercivity was studied for both routes. It is demonstrated that starting with the disorder state prior to HPT and annealing at low temperature (400°C) leads to the highest coercivity (about 1.8 kOe).

Mots clés: nanostructure; severe plastic deformation; coercivity; ordering; recrystallisation; intermetallic

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Abdelahad Chbihi, Xavier Sauvage, Cécile Genevois, Didier Blavette, Dmitry Gunderov, et al.. Optimization of the magnetic properties of FePd alloys by severe plastic deformation. Advanced Engineering Materials, 2010, 12 (8), pp.708. ⟨10.1002/adem.200900326⟩. ⟨hal-00683466⟩