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Title: Microstructure and mechanical properties of duplex stainless steel subjected to hydrostatic extrusion

The nanostructure and mechanical properties of ferritic-austenitic duplex stainless steel subjected to hydrostatic extrusion were examined. The refinement of the structure in the initial state and in the two deformation states (ε = 1.4 and ε = 3.8) was observed in an optical microscope (OM) and a transmission electron microscope (TEM). The results indicate that the structure evolved from microcrystalline with a grain size of about 4 μm to nanocrystalline with a grain size of about 150 nm in ferrite and 70 nm in austenite. The material was characterized mechanically by tensile tests performed in the two deformation states. The ultimate strength appeared to increase significantly compared to that in the initial deformation stages, which can be attributed to the grain refinement and plastic deformation. The heterogeneity observed in microregions results from the dual-phase structure of the steel. The results indicate that hydrostatic extrusion is a highly potential technology suitable for improving the properties of duplex steels. - Highlights: • Duplex stainless steel was hydro extruded to a total strain of 3.8 • After the last stage of deformation heterogeneous structure was obtained in the material • As a result of stresses non-diffusive transformation γ→α’ occurred in the material •more » Nanometric (sub)grains were obtained in the austenite regions.« less
Authors:
 [1] ; ;  [1] ;  [2] ;  [1]
  1. Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland)
  2. High Pressure Research Center, Polish Academy of Sciences, Sokołowska 29, 01-142 Warsaw (Poland)
Publication Date:
OSTI Identifier:
22340385
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 93; 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; 77 NANOSCIENCE AND NANOTECHNOLOGY; AUSTENITE; AUSTENITIC STEELS; CRYSTALS; DEFORMATION; FERRITE; FERRITES; FERRITIC STEELS; GRAIN REFINEMENT; GRAIN SIZE; NANOSTRUCTURES; PLASTICITY; STAINLESS STEELS; STRESSES; TRANSMISSION ELECTRON MICROSCOPY; ULTIMATE STRENGTH