Microstructure evolution and properties of Al/Al–Mg–Si alloy clad wire during heat treatment

Abstract

In this paper, heat treatment was carried out on Al/Al–Mg–Si alloy clad wire, and microstructure evolution and properties of Al/Al–Mg–Si alloy clad wire during heat treatment were investigated. During solution, contents of Mg and Si in inner matrix increased due to dissolution of primary Mg2Si, and they also increased in outer matrix because Mg and Si diffused across the interface. Tensile strength of the clad wire increased firstly and then decreased, and elongation continuously increased, while conductivity continuously decreased with the increase in solution time. In aging process, Mg2Si precipitated in both inner core and outer layer, and the content and average diameter of the precipitate increased with the increase in aging time. The content of precipitate was higher, and the average diameter was bigger in inner core. Tensile strength of the clad wire increased firstly and then decreased with the increase in aging time, and the elongation continuously decreased, while the conductivity continuously increased. The peak tensile strength of 202 MPa occurred at 8 h, when the corresponding elongation was 20 % and the conductivity reached 56.07 %IACS. Even tensile strength of the prepared clad wire approximately equaled to that of Al–0.5Mg–0.35Si alloy 203 MPa, the conductivity was obviously improved from 54.2 to 56.07 %IACS.