ESOMAT 2009, 05029 (2009)
DOI: 10.1051/esomat/200905029

Deformation microstructure of TRIP/TWIP Steels at the early deformation stages

X. Zhang¹, T. Sawaguchi², K. Ogawa², F. Yin² and X. Zhao<sup>1

1</sup>  Key Laboratory for Anisotropy and Texture of Materials, Northeastern University, Shenyang 110004, People’s Republic of China
²  Exploratory Materials Research Laboratory for Reliability and Safety, National Institute for Materials Science, Tsukuba 305-0047, Japan

zhang.xin@nims.go.jp

Published online: 1 September 2009

Abstract
Deformation microstructures of austenitic Fe-30Mn-(6-x)Si-xAl(x=2, 3 mass %) steels have been investigated at different nominal strains by the combined use of atomic force microscopy (AFM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). Three kinds of deformation products, i.e. planar dislocation bands, ε martensite plates and deformation twins are commonly formed on {111} habit planes and exhibit a plate-like morphology in AFM images. At the very early stage of plastic deformation the main microstructure of Fe-30Mn-4Si-2Al steel is ε martensite. Some of the ε maretensite plates transform to the deformation twins with increasing tensile strain. On the other hand, the main microstructures of Fe-30Mn-3Si-3Al are planar and wavy dislocations at the onset of plastic deformation. The deformation twins generate and increase as deformation proceeds. In spite of the quite different microstructures between the two alloys, they exhibit the similar deformation behavior with strain hardening rates comparable to each other.

© Owned by the authors, published by EDP Sciences 2009