A structural description for the F.C.C. → B.C.C. martensitic transformation in terms of {011} 〈011〉f.c.c. simultaneous double shear. Relation with the atomic configuration in {3, 15, 10}f.c.c. habit plane

Abstract

A Structural Description for the F.C.C. -+ B.C.C. Martensitic Transformation in Terms of (011) <Oll>f.c.c. Simultaneous Double Shear BY Relation with the Atomic Configuration in (3, 15, 10}i.o.c. Habit Plano A. LE LANN and A. DUBERTRET The model proposed allo.cvs a correlation to be established between the main experimental results and the movement of atoms during the transformation. This movement is defined with respect t o the (Oll)f.c.c, -( i l l ) b.c.c. close-packed rows which are "strain invariant rows" of the transformation. The homogeneous and heterogeneous part of the deformation result from the same kind of atom movement which can be described by (011) (Oll)f.c.c. transverse waves. A simple atomic configuration is proposed for the { 225)fC.,. and { 3, 15, 10}f.c.c. habit plane. The habit plane structure is correlated to the Kurdjumov-Sachs or Nishiyama orientation relations and to the symmetry conditions during the transformation. Le modBle propose Btablit une correlation entre les principaux rBsultats expbrimentaux et le mouvement des atomes pendant la transformation. Ce mouvement cst dBfini par rapport mix rangees compactes (OII)f.c,c. + (ill)b.c.c. de la structure qui demeurent sans distorsion. I1 peut 6tre dbcrit par des ondes transversales (011) (Oll)f,c.c. et permet d 'obtenir simultanBment la deformation homoghe de reseau et la deformation dite B reseau invariant. La structure des plans d'accolement { 225}f., c . et { 3, 15, 10}f.c.c. est expliquee B partir d'une configuration atomique simple, egalement relike au mouvement des atomes. On montre le lien existant entre les conditions de symetrie pendant la transformation, les relations d'orientation de type Kurdjumov-Sachs ou Nishiyama et la nature { 225}f.c.c. ou { 3, 15, 10}f.c.c. du plan d'accolement.