Effect of Mn or Fe Addition on Age-Hardening Behaviour of Al–Mg₂Si Alloys

Abstract

Microstructure and aging hardness variation of AlMgSi alloys with different Mn or Fe content were investigated to reveal the effect of Mn or Fe on the age hardening behavior of AlMgSi alloy using transmission electron microscopy. The peak hardness of the alloys with small content of Mn or Fe is higher than that of the base alloy; the peak hardness of the alloy with 0.2 at%Fe is similar to that of the base alloy but the peak hardness of the alloy with 0.25 at%Mn is lower than that of the base alloy. Si is expensed to form the dispersoid of AlMnSi or AlFeSi in the alloy with 0.25 at%Mn or 0.2 at%Fe. On the other hand, small Mn or Fe addition enhances the formation of ¢AA phase which is similar to Co-or Ni-addition alloys because Si is not expensed to form such dispersoid in Co-and Ni-addition alloys. It is thought that this will result in the difference of Si in the matrix for the formation of the precipitate.

Microstructure and mechanical behavior of Al9Si0.8Fe alloy with different Mn contents

“…Nowadays, Al-Si alloys are among the most popular casting alloys and have a wide range of applications in the automotive and aerospace industries because of their excellent abrasion resistance, low cost, low densities and acceptable mechanical properties [2][3][4]. In the continuing requirement for automobile weight reduction, the Al-Si alloys have been considered as the promising candidates for bodysheet materials [5].…”

Phase Transformations in the AlMg Alloys Driven by High‐Pressure Torsion

“…[ 5,9,10,12,13,17,20,35 ] The alloying with additional components modifies the precipitation sequence and, consequently, the resulted mechanical properties. [ 18–38 ] The plastic deformation of AlMg‐based alloys significantly affects the microstructure stability during following isothermal aging. It is because of the large density of dislocations.…”

“…The AlMg binary alloys [ 1,2 ] are the base for the various ternary (mainly AlMgSi) [ 3–17 ] and multicomponent [ 18–38 ] Al‐based industrial alloys. Their unique mechanical properties are controlled by the formation of Guinier–Preston (GP) zones, metastable and stable intermetallic phases during thermal [ 3,9,10,12,13,17–19,30,35 ] and mechanical [ 6,7,9,11,15,31,35 ] pretreatment, and natural and artificial ageing.…”