The Effect of Processing Pass on the Microstructure and Mechanical Properties of a Friction Stir Processed As-Cast Mg-6 wt % Sn Alloy

Yang Zhang,Xiaoping Li,Feilong Li,Xiaoyang Chen,Yalin Lu,Xiyun Qin

doi:10.3390/met8110906

Abstract

In this study, as-cast Mg-6 wt % Sn alloy is subjected to one-pass and two-pass friction stir processing (FSP). The effect of processing pass on microstructure and mechanical properties of FSP Mg-6Sn alloy is investigated. It is found that one-pass FSP leads to the breakage and partial dissolution of the Mg2Sn phase in the stir zone (SZ) and two-pass FSP leads to the further dissolution and dynamic precipitation of the Mg2Sn phase. Dynamic recrystallization (DRX) takes place in the SZ of an Mg-6Sn alloy undergoing FSP. Compared to one-pass FSP, two-pass FSP brings about further grain refinement in the SZ. A strong {0001} basal texture is developed in the SZ of a Mg-6Sn alloy from FSP and the change of the sample region or processing pass has little influence on the texture. Compared to an as-cast Mg-6Sn sample, one-pass FSP brings about significant improvement in mechanical properties. Two-pass FSP leads to the further increase in yield strength (YS) and ultimate tensile strength (UTS) but elongation (EL) is reduced. The continuous increase in strength is attributed to the grain refinement and the dissolution and dynamic precipitation of Mg2Sn phase achieved by FSP.

Highlights

In the face of challenges from increasing energy consumption and pollution emissions, the application of Mg alloys in transportation and aviation industries has gained considerable attention due to their significant advantages in weight reduction
Two-pass friction stir processing (FSP) led to the further dissolution of Mg2Sn particles and the volume fraction of the Mg2Sn reduced compared to the FSP1 sample
As-cast Mg-6Sn alloy was subjected to FSP for one-pass or two-passes and the effect of processing pass on microstructure and mechanical properties of an Mg-6Sn alloy created using FSP

Summary

Introduction

In the face of challenges from increasing energy consumption and pollution emissions, the application of Mg alloys in transportation and aviation industries has gained considerable attention due to their significant advantages in weight reduction. The development of high-performance Mg alloys receives constant attention [1,2,3]. Mg-Sn alloys have been recognized as potential heat-resistant Mg alloys with an engineering application value in recent years [4,5,6]. Since the Sn element is an essential trace element in the human body and noncytotoxic, Mg-Sn alloys are promising bio-Mg alloys used as a bio-implant material [7,8]. The study of Mg-Sn alloys is of essential research value

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