Enhanced Mechanical Properties and Electrical Conductivity in Ultrafine-Grained Al 6101 Alloy Processed via ECAP-Conform

• Main Authors: Maxim Murashkin, Andrey Medvedev, Vil Kazykhanov, Alexander Krokhin, Georgy Raab, Nariman Enikeev, Ruslan Z. Valiev
• Format: Article
• Language: English
• Published: MDPI AG 2015-11-01
• Series: Metals
• Subjects: Al alloy; severe plastic deformation; equal channel angular pressing-Conform; ultrafine grained structure; aging; strength; electrical conductivity
• Online Access: http://www.mdpi.com/2075-4701/5/4/2148

This paper studies the effect of equal channel angular pressing-Conform (ECAP-C) and further artificial aging (AA) on microstructure, mechanical, and electrical properties of Al 6101 alloy. As is shown, ECAP-C at 130 °C with six cycles resulted in the formation of an ultrafine-grained (UFG) structure with a grain size of 400–600 nm containing nanoscale spherical metastable β′ and stable β second-phase precipitates. As a result, processed wire rods demonstrated the ultimate tensile strength (UTS) of 308 MPa and electrical conductivity of 53.1% IACS. Electrical conductivity can be increased without any notable degradation in mechanical strength of the UFG alloy by further AA at 170 °C and considerably enhanced by additional decomposition of solid solution accompanied by the formation of rod-shaped metastable β′ precipitates mainly in the ultrafine grain interior and by the decrease of the alloying element content in the Al matrix. It is demonstrated that ECAP-C can be used to process Al-Mg-Si wire rods with the specified UFG microstructure. The mechanical strength and electrical conductivity in this case are shown to be much higher than those in the industrial semi-finished products made of similar material processed by the conventional T6 or T81 treatment.