Decomposition process in a FeAuPd alloy nanostructured by severe plastic deformation

Xavier Sauvage (1) , Abdelahad Chbihi (1) , Dmitry Gunderov (2) , E.V. Belozerov (3) , A.G. 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

The decomposition process mechanisms have been investigated in a Fe50Au25Pd25 (at.%) alloy processed by severe plastic deformation. Phases were characterized by X-ray diffraction and microstructures were observed using transmission electron microscopy. In the coarse grain alloy homogenized and aged at 450°C, the bcc Α-Fe and fcc AuPd phases nucleate in the fcc supersaturated solid solution and grow by a discontinuous precipitation process resulting in a typical lamellar structure. The grain size of the homogenized FeAuPd alloy was reduced in a range of 50 to 100nm by high pressure torsion. Aging at 450°C this nanostructure leads to the decomposition of the solid solution into an equi-axed microstructure. The grain growth is very limited during aging and the grain size remains under 100nm. The combination of two phases with different crystallographic structures (bcc Α-Fe and fcc AuPd ) and of the nanoscaled grain size gives rise to a significant hardening of the alloy

Mots clés: Severe plastic deformation; phase transformation; discontinuous precipitation; nanocrystalline material

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

Xavier Sauvage, Abdelahad Chbihi, Dmitry Gunderov, E.V. Belozerov, A.G. Popov. Decomposition process in a FeAuPd alloy nanostructured by severe plastic deformation. Journal of Materials Science, 2008, 43, pp.7293-7298. ⟨10.1007/s10853-008-2752-5⟩. ⟨hal-00351002⟩