The improvement mechanism of good matching between electrical conductivity and mechanical properties for Al-4Si-0.8Mg-0.6Fe alloy

The contradictory relationship between electrical conductivity (abbreviate to EC) and mechanical properties limits the development of conductive aluminum alloys obviously. Nowadays, it is a challenge to put forward a strategy to improve EC and mechanical properties of Al alloy simultaneously. In this paper, composite boron treatment, alloying treatment, hot extrusion and heat treatment were proceed to improve the EC and mechanical properties of Al-4Si-0.8Mg-0.6Fe alloy and the corresponding improvement mechanism was analyzed. Through the above processes, Al matrix is purified and a large amount of plate-like Si are refined into equiaxed form with rod-like. What’s more, granular Fe/Mg-rich phases with small size as precipitations make main contribution to the excellent mechanical properties. Finally, a new Al-4Si-0.8Mg-0.6Fe alloy with good matching between electrical conductivity and mechanical properties was fabricated and its EC, vickers hardness (HV), Yield strength (YS), ultimate tensile strength and elongation are (52.1 ± 0.3) %IACS, (80 ± 1) HV, (194 ± 3) MPa, (227 ± 3) MPa, and (18.9 ± 0.2)%, respectively.