Enhanced strength and electrical conductivity of ultrafine-grained Al-Mg-Si alloy processed by hydrostatic extrusion

Journal Article · Mon Jan 15 00:00:00 EST 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2017.11.023· OSTI ID:22804850

Majchrowicz, Kamil; Zbigniew, Pakiela; Chrominski, Witold ^[1]; Kulczyk, Mariusz ^[2]

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1. Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland)
2. Institute of High Pressure Physics of the Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warsaw (Poland)

Highlights: • Al-Mg-Si alloy was subjected to hydrostatic extrusion combined with aging treatment. • UFG Al-Mg-Si alloy with UTS of 332 MPa and conductivity of 58% IACS was obtained. • Precipitation process depended on applied strains and crystallographic texture. • Strengthening effect was achieved by UFG structure and needle-like β″ precipitates. • Precipitation of β″ and spherical β′/β particles at GB provided high conductivity. - Abstract: The effect of hydrostatic extrusion combined with an artificial aging on microstructure, mechanical and electrical properties of 6101 Al-Mg-Si alloy was investigated. It has been shown that such thermo-mechanical treatment is an effective method for producing of long wires with an ultrafine-grained microstructure (grain size of 300–400 nm) and enhanced ultimate tensile strength (> 330 MPa) and electrical conductivity (up to 58% IACS). The mechanical behavior of 6101 Al-Mg-Si alloy depended strongly on applied strains by hydrostatic extrusion and crystallographic texture. Higher accumulative strain accelerated the precipitation kinetics but decreased the age hardening response. The double fiber <100> and <111> texture was observed for hydrostatically extruded samples. The <001> grains with homogenously distributed needle-like β″ precipitates provided precipitation strengthening of material while <111> grains resulted in more efficient grain boundary strengthening. Quantitative microstructure characterization allowed adjusting physical model to estimate the electrical conductivity and compare it with experimental data. The high conductivity was provided mainly by decomposition of solid solution due to precipitation of needle-like β″ precipitates in the grain interior and spherical β′ or β particles located at grain boundaries.

• OSTI ID: 22804850
• Journal Information: Materials Characterization, Vol. 135; Other Information: Copyright (c) 2017 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
ALUMINIUM COMPOUNDS
CRYSTALLOGRAPHY
DECOMPOSITION
ELECTRIC CONDUCTIVITY
EXTRUSION
FIBERS
GRAIN BOUNDARIES
GRAIN SIZE
MAGNESIUM COMPOUNDS
PRECIPITATION
PRESSURE RANGE MEGA PA 100-1000
SILICON COMPOUNDS
SOLID SOLUTIONS
TENSILE PROPERTIES
TERNARY ALLOY SYSTEMS
THERMOMECHANICAL TREATMENTS