Comparative Study of the Metallurgical Quality of Primary and Secondary AlSi10MnMg Aluminium Alloys

Asier Bakedano,Gorka Plata,Carlos Berlanga-Labari,Jokin Lozares,Andrea Niklas,Ana Isabel Fernández-Calvo

doi:10.3390/met11071147

Asier Bakedano, Gorka Plata + Show 4 more

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https://doi.org/10.3390/met11071147

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Abstract

The use of secondary aluminium is increasingly being promoted in the automotive industry for environmental reasons. The purpose of this study was to demonstrate that it is possible to obtain a recycled AlSi10MnMg(Fe) aluminium alloy with equal metallurgical quality to that of a primary AlSi10MnMg alloy when an adequate melt treatment is applied. The melt treatment consisted of deoxidation, degassing and skimming in accordance with the detailed procedure described in this article. The metallurgical qualities of one primary and two secondary alloys were assessed using thermal analysis, the density index test, the macroinclusion test and the microinclusion level test before and after melt treatment. The thermal analysis allowed us to compare the variables of the solidification cooling curve (Al primary temperature and its undercooling; Al-Si eutectic temperature and its predictive modification rate). The density index test was used to evaluate the hydrogen gas content in the melt. The macroinclusion test was used to evaluate the melt cleanliness, while the microinclusion level test was used to perform the inclusion identification and quantification analyses. This study showed the feasibility of manufacturing structural components using 100% recycled secondary aluminium alloy through V-HPDC technology.

Highlights

The primary aluminium alloy AlSi10MnMg is the most widely used alloy for manufacturing structural components in the automotive market, such as front shock towers, door frames and rear longitudinal members
Up to 80% of the aluminium structural components made through vacuum high-pressure die casting (V-HPDC) are produced using this alloy [1]
Considering the UNE-EN-1706:2020 standard as a reference, the minimum elongation required for the AlSi9Cu3(Fe)(Zn) alloy is 1% in the F state, whereas for a V-HPDC component cast in AlSi10MnMg, a minimum elongation of 12% is required after

Summary

Introduction

The primary aluminium alloy AlSi10MnMg is the most widely used alloy for manufacturing structural components in the automotive market, such as front shock towers, door frames and rear longitudinal members. Up to 80% of the aluminium structural components made through vacuum high-pressure die casting (V-HPDC) are produced using this alloy [1]. The main differences between the components of conventional high-pressure die casting (HPDC) technology and V-HPDC technology are the ductility or energy absorption capacity [3] and the ability of the latter to be heat-treated and welded [4,5]. Considering the UNE-EN-1706:2020 standard as a reference, the minimum elongation required for the AlSi9Cu3(Fe)(Zn) alloy (the most used secondary alloy in conventional HPDC process [6,7,8]) is 1% in the F state, whereas for a V-HPDC component cast in AlSi10MnMg, a minimum elongation of 12% is required after

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