Effect of Si Addition on Solid Solution Hardening of Al-Mn Alloys

Abstract

Non-heat-treatable aluminum alloys owe their strength mainly to elements in solid solution. But the effect of the combination of multiple elements on strength is not well known. Small amounts of Si usually exist in many commercial alloys. Three high purity based Al-Mn binary alloys and one ternary alloy with addition of Si are investigated in this work. The varied solute contents are achieved by cast compositions and the grain structures are controlled by recrystallization. The strength is measured by tensile tests at room temperature. It is found that the addition of Si to Al-Mn alloys leads to a similar increase in strength as adding a similar amount of Mn.