J. Phys. IV France 112 (2003) 319
Interphase boundary structures of lath martensite and bainite in steelT. Furuhara, N. Miyajima, T. Moritani and T. Maki
Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
Interphase boundary structures of lath martensite and bainite formed in austenite were examined by means of conventional and high-resolution transmission electron microscopy. Orientation relationships of the isothermal lath martensite in Fe-20Ni-5.5Mn and of the bainitic ferrite in Fe-2Si-IMn-O.6C are both slightly scattered in the vicinity of K-S, N and G-T relationships with respect to austenite. The broad face of martensite lath contains transformation dislocations (monoatomic steps with the (111) //(011) terrace). Two kinds of accommodation dislocations exist alternately on every three layers of the parallel close packed planes, in a glissile arrangement. Such dislocations can fully accommodate the shear component of transformation strain. It is found that the atomic structure of bainitic ferrite/austenite interphase boundary is similar to that of lath martensite.
© EDP Sciences 2003