Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena

Xavier Sauvage (1) , Gerhard Wilde (2) , Sergiy Divinski (2) , Zenji Horita (3) , Ruslan Valiev (4)

1 GPM - Groupe de physique des matériaux
2 Institute of Materials Physics
3 Department of Material Science and Engineering [Fukuoka]
4 IPAM - Institute for Physics of Advanced Materials

Grain boundaries in ultrafine grained (UFG) materials processed by severe plastic deformation (SPD) are often called "non-equilibrium" grain boundaries. Such boundaries are characterized by excess grain boundary energy, presence of long range elastic stresses and enhanced free volumes. These features and related phenomena (diffusion, segregation, etc.) have been the object of intense studies and the obtained results provide convincing evidence of the importance of a non-equilibrium state of high angle grain boundaries for UFG materials with unusual properties. The aims of the present paper are first to give a short overview of this research field and then to consider tangled, yet unclear issues and outline the ways of oncoming studies. A special emphasis is given on the specific structure of grain boundaries in ultrafine grained materials processed by SPD, on grain boundary segregation, on interfacial mixing linked to heterophase boundaries and on grain boundary diffusion. The connection between these unique features and the mechanical properties or the thermal stability of the ultrafine grained alloys is also discussed.

Mots clés: Severe Plastic Deformation; Grain Boundary; Segregation; diffusion

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

Xavier Sauvage, Gerhard Wilde, Sergiy Divinski, Zenji Horita, Ruslan Valiev. Grain boundaries in ultrafine grained materials processed by severe plastic deformation and related phenomena. Materials Science and Engineering: A, 2012, 540, pp.1. ⟨10.1016/j.msea.2012.01.080⟩. ⟨hal-00683535⟩