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Title: Evaluation of microstructure anisotropy on room and medium temperature ECAP deformed F138 steel

The microstructure developed during severe plastic deformation results in improved mechanical properties because of the decrease in domain sizes and accumulation of defects, mainly dislocation arrays. The characteristic deformation stages observed in low stacking fault energy (SFE) face centered cubic (FCC) materials are highly influenced by the development of the primary and secondary twinning that compete with dislocation glide. In this paper, a low SFE F138 stainless steel is deformed by equal channel angular pressing (ECAP) up to 4 passes at room temperature (RT) and at 300 °C to compare the grain refinement and twin boundary development with increasing deformation. Tensile tests were performed to determine the deformation stages reached by the material before and after ECAP deformation, and the resulting microstructure was observed by TEM. X-ray diffraction and EBSD, average technique the first and local the second one, were used to quantify the microstructural changes, allowing the determination of diffraction domain sizes, dislocation and stacking fault densities and misorientation indices, which lead to a complete analysis of the deformation introduced in the material, with comparative correlations between various microstructural parameters. - Highlights: • The microstructure of ECAP pressed F138 steel was studied using TEM, EBSD and XRD. • Increasingmore » deformation reduced domain sizes and increased dislocation densities. • Dislocation array compactness and misorientation increased with higher deformation. • Largest dislocation densities, mostly screw, match with simultaneous activation of twins. • Several correlations among microstructural features and parameters have been disclosed.« less
Authors:
 [1] ; ;  [2] ;  [1] ;  [3] ;  [1]
  1. Instituto de Física Rosario, FCEIA-UNR-CONICET, Bv. 27 de Febrero 210 bis, S2000EZP Rosario (Argentina)
  2. Departamento de Engenharia de Materiais — Universidade Federal de São Carlos, Rodovia Washington Luís, km 235 — SP-310, São Carlos, SP 13565-905 (Brazil)
  3. Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastr.6, 38678 Clausthal-Zellerfeld. Helmholtz-Zentrum Geesthacht, GEMS Outstation, Notkestr. 85, 22607 Hamburg (Germany)
Publication Date:
OSTI Identifier:
22476156
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 107; Other Information: Copyright (c) 2015 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; ANISOTROPY; BACKSCATTERING; DEFECTS; DEFORMATION; DISLOCATIONS; ELECTRON DIFFRACTION; FASTENERS; FCC LATTICES; MICROSTRUCTURE; PLASTICITY; STACKING FAULTS; TEMPERATURE RANGE 0273-0400 K; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION