Deformation and fracture of interfaces in metallic materials
Focus: Role of the interface in the deformation and fracture behavior of nanolaminate metallic systems have been studied in-situ in the SEM.
Semi-brittle metallic structures with oriented interfaces exhibited interface dominated fracture behavior and were therefore a part of this study. Lamellar TiAl based alloys are known to be highly anisotropic in their mechanical properties due to their laminate structure. Thus a crack propagating along the interface and across it is bound to show different trajectories and micro-mechanisms.
Similar behavior was expected along inter-lamellar boundaries of cold drawn pearlitic steels, which are an oriented nanocomposite of ferrite and cementite lamellae.
This project dealed with quantifying interface fracture as well as studying fracture micro-mechanisms when a crack is oriented at different angles to the interface.
Fig Caption: (a) Load (P) vs displacement (d) curve obtained from microclamped beam bending of pearlitic steel cold drawn to a strain of 5. (b) represents the different stages of fracture corresponding to the points in the P-d curve. (c) shows the specimen after fracture including the nanolaminate structure of the composite in the background.