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Title: Microstructure evolution and mechanical behavior of a high strength dual-phase steel under monotonic loading

Transmission electron microscopy (TEM) microstructures of a high-strength dual-phase steel DP800 have been examined after moderate plastic deformations in simple shear and uniaxial tension. Special attention has been paid to the effect of the intergranular hard phase (martensite) on the microstructure evolution in the near-grain boundary regions. Quantitative parameters of dislocation patterning have been determined and compared with the similar characteristics of previously examined single-phase steels. The dislocation patterning in the interiors of the ferrite grains in DP800 steel is found to be similar to that already observed in the single-phase IF (Interstitial Free) steel whereas the martensite-affected zones present a delay in patterning and display very high gradients of continuous (gradual) disorientations associated with local internal stresses. The above stresses are shown to control the work-hardening of dual-phase materials at moderate strains for monotonic loading and are assumed to influence their microstructure evolution and mechanical behavior under strain-path changes. - Highlights: • The microstructure evolution has been studied by TEM in a DP800 steel. • It is influenced by both martensite and dislocations in the initial state. • The DP800 steel presents a high work-hardening rate due to internal stresses.
Authors:
 [1] ;  [2] ;  [3]
  1. CRISM Prometey, St Petersburg 193015 (Russian Federation)
  2. Laboratoire Roberval, UMR-CNRS 7337, Université de Technologie de Compiègne, Centre de Recherches de Royallieu, CS 60319, 60203 Compiègne Cedex (France)
  3. CNRS, Laboratoire des Sciences des Procédés et des Matériaux, UPR 3407, Université Paris 13, Sorbonne Paris Cité, F-93430 Villetaneuse (France)
Publication Date:
OSTI Identifier:
22476041
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 100; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DISLOCATIONS; FERRITES; GRAIN BOUNDARIES; MARTENSITE; PLASTICITY; RESIDUAL STRESSES; STEELS; STRAIN HARDENING; STRAINS; TRANSMISSION ELECTRON MICROSCOPY