Open Access

ARTICLE

Deformation and Failure of Single-Packets in Martensitic Steels

by T.M. Hatem¹, M.A. Zikry¹

1 Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695-7910, USA.

Computers, Materials & Continua 2010, 17(2), 127-148. https://doi.org/10.3970/cmc.2010.017.127

Abstract

A three-dimensional multiple-slip dislocation-density-based crystalline formulation, and specialized finite-element formulations were used to investigate dislocation-density evolution and crack behavior in single-packet lath martensite in high strength martensitic steels. The formulation is based on accounting for variant morphologies and orientations, and initial dislocations-densities that are uniquely inherent to martensitic microstructures. The effects of loading plane with respect to the orientation o the habit plane are investigated. Furthermore, the formulation was used to investigate single-packet microstructure mapped directly from SEM/EBSD images of maraging and ausformed martensitic steel alloys. This analysis underscores that shear pipe effects in martensitic steels, where the long direction of the laths is aligned with specific slip-directions, can result in shear-strain localization along specific variants. Furthermore, the results indicate that the strength and ductility are higher for the loading plane parallel to the habit plane as compared to those normal to the habit plane.

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