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

Journal Article · Tue Sep 15 00:00:00 EDT 2015 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2015.06.035· OSTI ID:22476156

Kliauga, A.; Ferrante, M. ^[1]; Avalos, M. ^[2]; Brokmeier, H. -G. ^[3]; Bolmaro, R. E. ^[2]

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1. Departamento de Engenharia de Materiais — Universidade Federal de São Carlos, Rodovia Washington Luís, km 235 — SP-310, São Carlos, SP 13565-905 (Brazil)
2. Instituto de Física Rosario, FCEIA-UNR-CONICET, Bv. 27 de Febrero 210 bis, S2000EZP Rosario (Argentina)
3. Institut für Werkstoffkunde und Werkstofftechnik, TU Clausthal, Agricolastr.6, 38678 Clausthal-Zellerfeld. Helmholtz-Zentrum Geesthacht, GEMS Outstation, Notkestr. 85, 22607 Hamburg (Germany)

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. • Increasing 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.

• OSTI ID: 22476156
• Journal Information: Materials Characterization, Vol. 107; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

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