Effect of Sn content on the mechanical properties and corrosion behavior of Mg-3Al-xSn alloys

Zhaochen Yu,Wentao Zhang,Zhi Hu,Honggun Song,Qianfei Huang,Hongyu Guan,Chao Luo,Yang Chen,Chassagne Luc

doi:10.1088/2053-1591/aba149

Abstract

The effect of Sn content on the mechanical properties and corrosion behavior of Mg-3Al-xSn alloys was investigated by SEM-EDXS, XRD, electrochemical measurements, and scanning Kelvin probe force microscopy (SKPFM). The results showed that when the Sn content was 1.4 wt%, Sn dissolved in the α-Mg matrix and then precipitated as an intermetallic compound (Mg2Sn). The combined results of mass loss, hydrogen evolution, and electrochemical measurements indicated that Mg-3Al-1Sn had a low corrosion rate. The SKPFM results showed that the Volta potential of Mg2Sn particles, Al-Mn, and β-Mg17Al12 phases were 100, 80, and 50 mV higher than the matrix, respectively. Therefore, the Mg2Sn phase that formed in Mg-3Al-xSn served as a local cathode due to its high potential, which accelerated microgalvanic corrosion along with the secondary local cathode (Al-Mn). The Sn solution strengthening and secondary phase strengthening (fine Mg2Sn particles) improved the mechanical properties of the Mg-3Al-xSn alloys.

Highlights

Over the past decade, Mg-Al series alloys have been widely used due to their low density, high specific strength, good electrical conductivity, and easy mechanical processing [1,2,3]
Excessive Sn addition to Mg alloys can result in the formation of Mg2Sn intermetallic compounds, which increase the hydrogen evolution rate and deteriorate the corrosion resistance of as-cast AM70 magnesium alloys [16, 17]
The chemical compositions of the specimens were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the results are shown in table 1

Summary

July 2020

The effect of Sn content on the mechanical properties and corrosion behavior of Mg-3Al-xSn alloys and DOI. The results showed that when the Sn content was 1.4 wt%, Sn dissolved in the α-Mg matrix and precipitated as an intermetallic compound (Mg2Sn). The combined results of mass loss, hydrogen evolution, and electrochemical measurements indicated that Mg-3Al-1Sn had a low corrosion rate. The SKPFM results showed that the Volta potential of Mg2Sn particles, Al-Mn, and β-Mg17Al12 phases were 100, 80, and 50 mV higher than the matrix, respectively. Mg2Sn phase that formed in Mg-3Al-xSn served as a local cathode due to its high potential, which accelerated microgalvanic corrosion along with the secondary local cathode (Al-Mn). The Sn solution strengthening and secondary phase strengthening (fine Mg2Sn particles) improved the mechanical properties of the Mg-3Al-xSn alloys

Introduction

Experimental procedure

Results

Discussions

Conclusions