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Title: Strengthening of Cu–Ni–Si alloy using high-pressure torsion and aging

An age-hardenable Cu–2.9%Ni–0.6%Si alloy was subjected to high-pressure torsion. Aging behavior was investigated in terms of hardness, electrical conductivity and microstructural features. Transmission electron microscopy showed that the grain size is refined to ∼ 150 nm and the Vickers microhardness was significantly increased through the HPT processing. Aging treatment of the HPT-processed alloy led to a further increase in the hardness. Electrical conductivity is also improved with the aging treatment. It was confirmed that the simultaneous strengthening by grain refinement and fine precipitation is achieved while maintaining high electrical conductivity. Three dimensional atom probe analysis including high-resolution transmission electron microscopy revealed that nanosized precipitates having compositions of a metastable Cu{sub 3}Ni{sub 5}Si{sub 2} phase and a stable NiSi phase were formed in the Cu matrix by aging of the HPT-processed samples and these particles are responsible for the additional increase in strength after the HPT processing. - Highlights: • Grain refinement is achieved in Corson alloy the size of ∼150nm by HPT. • Aging at 300°C after HPT leads to further increase in the mechanical property. • Electrical conductivity reaches 40% IACS after aging for 100 h. • 3D-APT revealed the formation of nanosized-precipitates during aging treatment. • Simultaneous hardeningmore » in both grain refinement and precipitation is achieved.« less
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [2]
  1. Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan)
  2. (I2CNER), Kyushu University, Fukuoka 819-0395 (Japan)
  3. University of Rouen, CNRS UMR 6634, Groupe de Physique des Matériaux, Faculté des Sciences, BP 12, 76801 Saint-Etienne du Rouvray (France)
Publication Date:
OSTI Identifier:
22340347
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 90; 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; AGING; ELECTRIC CONDUCTIVITY; GRAIN REFINEMENT; GRAIN SIZE; HARDENING; MICROHARDNESS; NANOSTRUCTURES; PARTICLES; PRECIPITATION; SILICON ALLOYS; TORSION; TRANSMISSION ELECTRON MICROSCOPY