J. Phys. IV France
Volume 05, Numéro C8, Décembre 1995
International Conference on Martensitic Transformations – ICOMAT 95
Page(s) C8-161 - C8-166
International Conference on Martensitic Transformations

J. Phys. IV France 05 (1995) C8-161-C8-166

DOI: 10.1051/jp4:1995820

Lattice Transitions and Flickering Images in Aged Cu-Mn Alloys

J. Perkins1, K. Adachi2 and T. Yamashita3

1  Monterey Institute of Advanced Studies, P.O. Box 975, Monterey, CA 93942-0975, U.S.A.
2  Sumitomo Metal Mining Co., Central Research Lab., Ichikawa 272, Japan
3  Naval Postgraduate School, Materials Science Group, Monterey, CA 93943, U.S.A.

Distinctive "flickering" movements are observed in TEM images of the microstructure of Cu-Mn alloys after aging within the miscibility gap. Analyses of two-beam image extinction and electron diffraction streaks indicate that the underlying tweed and "V-shaped" images involve a static displacement field of the type {110} <1-10>. Atomic force microscopy and other microanalyses show the presence of Mn-enriched colonies of 15-40 nm, formed throughout the microstructure, in which twinned fct crystallites are induced and confined. The flickering movements are interpreted as a direct manifestation of the fcc→fct transformation event and in particular of a rotation of the fct c-axis, these effects being caused by an inelastic interaction between <110> <1-10> phonons and the accelerated electrons of the incident TEM beam.

© EDP Sciences 1995