An assessment of the contributing factors to the superior properties of a nanostructured steel using in situ high-energy X-ray diffraction
Received 14 September 2009; received in revised form 9 December 2009; accepted 14 December 2009. published online 04 January 2010.
Abstract
In contrast to most nanostructured materials, outstanding mechanical property has been demonstrated in a nanostructured metastable austenitic steel, owing to the new characteristics of deformation-induced martensitic transformation. In this paper, by employing an in situ high-energy X-ray diffraction technique, we explore these characteristics by examining factors from the load partitioning, Lüders banding, to texture development. It was found that the martensitic transformation was mainly driven through Lüders band propagation. Marked load transfer takes place from austenite to martensite as Lüders band propagates, and continues into the homogeneous deformation regime. The texture development is mostly contributed by martensitic transformation, but dislocation-based plasticity also plays a role. The effective load partitioning along with the deformability of martensite promotes sample ductility.
aDepartment of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
bNeutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 39831, USA
cSchool of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
dAdvanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
eDepartment of Metallurgical Engineering, Yonsei University, Seoul 120-749, South Korea
Corresponding author. Address: Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA. Tel.: +1 865 974 2683; fax: +1 865 974 4115.
ABSTRACT