Enhanced strength and electrical conductivity of Al-Mg-Si alloy by thermo-mechanical treatment

In the present work, two types of thermo-mechanical treatments were performed to enhance the mutually contradictory strength and electrical conductivity of Al-Mg-Si alloy. The microstructures, conducting and mechanical behavior of the alloy during conventional artificial aging treatment (solution treating, aging) and thermo-mechanical treatments (solution treating, cold rolling, aging and solution treating, pre-aging, cold rolling, re-aging) were investigated. The results indicate that the Al-Mg-Si alloy after 70% cold rolling and aging at 180 degrees C for 6 h reveals higher ultimate tensile strength and electrical conductivity (being 267 MPa and 58.2% IACS) than the conventional peak-aged alloys do (being 248 MPa and 54.8% IACS). Further simultaneously enhanced ultimate tensile strength and electrical conductivity, as high as 301 MPa and 58.9% IACS, respectively, can be acquired for the alloy after pre-aging at 180 degrees C for 2 h and then 70% cold rolling followed by re-aging at 180 degrees C for 6 h. With the aid of the microstructure evolution, the factors which lead to the simultaneously enhanced strength and conductivity of the alloy are discussed in detail. (C) 2015 Elsevier B.V. All rights reserved.