Effect of Zn and Mg Content on Crashworthiness of Al-Zn-Mg Alloy Thin-Walled Square Extrusions.

Hui Guo,Cheng Wang,Yunlai Deng,Jin Zhang

doi:10.3390/ma13214791

Abstract

The effects of Zn and Mg content in thin-walled square extrusions of Al-Zn-Mg alloys on its crashworthiness were investigated, and the correlation between the crushing properties, mechanical properties, and microstructures of the profiles were investigated. The results showed that the strength and the compression properties were gradually increased with a decrease in the Zn/Mg ratios (from 12.48 to 4.57). When the Zn/Mg ratio is lower (less than 6.29), an increase in the Mg content simultaneously improves the alloy strength and the compression properties. An increase in Zn content (from 5.07 to 6.77) can improve the strength of the alloy however, it does not affect the compression properties. However, the higher Zn contents (6.77%) would lead to cracking in advance during the compressing, which reduces the compression energy absorption capacities of the product. Therefore, in order to obtain higher strength and excellent compression properties, the Zn/Mg ratio should be reduced. For the upper limit, the Zn content should not be too high (less than 6.77), as this may lead to early cracking and failure. For the lower limit, the Mg content should be higher (more than 0.91) to make sure that the alloy has excellent compression properties and higher strength.

Highlights

Owing to the high energy absorption and weight efficiencies of thin-walled aluminum alloy extrusions with cavity sections, they are often used as collision-energy absorption components in vehicles
The mechanical properties of the profile samples with different main compositions made by the same process were significantly the profile samples with different main compositions made by the same process were significantly different, in which the yield strength ranged from 270 MPa to 400 MPa and the tensile strength ranged different, in which the yield strength ranged from 270 MPa to 400 MPa and the tensile strength ranged from 310 MPa to 431 MPa
The yield strength ranged from 270 MPa to 400 MPa, and the tensile strength ranged from 310 MPa to 431 MPa

Summary

Introduction

Owing to the high energy absorption and weight efficiencies of thin-walled aluminum alloy extrusions with cavity sections, they are often used as collision-energy absorption components in vehicles. Several experimental and numerical studies have been conducted to optimize the energy absorbing capacity of aluminum alloy extrusion profiles under axial crushing. Most of these studies have focused on obtaining an optimum structural design. Sun et al [5] found that the increasing number of corners on the cross-section of multicorner tubes improved the energy absorption performance of 6060 aluminum alloy thin-walled square tubes. They obtained a maximum crushing force efficiency of 11.6%, which was higher than that of the square tubes made with the same material. Acar et al [7] evaluated 30

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