Crystallographic analysis of slip transfer mechanisms across the ferrite/cementite interface in carbon steels with fine lamellar structure

Abstract

The results of crystallographic analysis of deformation transfer mechanisms across the ferrite/cementite interface in fine lamellar pearlite are presented. The possibility of a strain transfer was evaluated using the LRB criteria that are used for the slip transfer mechanisms across grain boundaries [Lee, Robertson & Birnbaum (1989).Scr. Metall.23, 799–803; (1990).Metall. Trans. A,21, 2437–2447; (1990).Philos. Mag. A,62, 131–153]. Dislocation reactions at the Fe/Fe3C interface were studied, taking into account Bagaryatsky and Isaichev orientation relationships between ferrite and cementite observed for fine lamellar pearlite. Slip planes and Burgers vectors of full and partial dislocations in cementite have been proposed on the basis of the results of atomistic simulations of stacking faults for some planes of cementite. It has been found that strain transfer through the Fe/Fe3C interface is possible only for half of the slip systems 1/2〈111〉{110}Fand for quarter of the slip systems 1/2〈111〉{112}Fof ferrite. Other slip systems do not cross the interface and are involved in the hardening of the ferrite phase of pearlite.