Rev.Adv.Mater.Sci. (RAMS)
No 1/2, Vol. 47, 2016, pages 16-25

MICROSTRUCTURE, STRENGTH, ELECTRICAL CONDUCTIVITY AND HEAT RESISTANCE OF AN Al-Mg-Zr ALLOY
AFTER ECAP-CONFORM AND COLD DRAWING

M.Yu. Murashkin, .E. Medvedev, V.U. Kazykhanov, G.I. Raab, I.A. Ovid'ko
and R.Z. Valiev

Abstract

This paper describes the routes to process conducting materials based on the Al-Mg-Zr system combining high strength (UTS=267 MPa), electrical conductivity (over 57% IACS) and heat resistance (up to 150). These properties in the alloy with 0.4 wt.% Mg and 0.2 wt.% Zr are achieved through the formation of ultrafine-grained microstructure (UFG) by thermomechanical treatment (TMT), including annealing, severe plastic deformation (SPD) via equal channel angular pressing-Conform (ECAP-C) followed by cold drawing. The mechanical strength is enhanced by the formation of ultrafine grains during ECAP-C and their additional refinement through cold drawing. Also, ECAP-C and drawing result in the material strengthening due to increased dislocation density. The annealing of the alloy prior to SPD is used to provide a good heat resistance and high electrical conductivity via formation of nanoscale Al3Zr metastable precipitates and, correspondingly decreasing the concentration of Zr atoms in the Al solid solution.

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