Effect of Sn Content on the Microstructure, Mechanical Properties and Corrosion Behavior of Biodegradable Mg–x (1, 3 and 5 wt.%) Sn–1Zn–0.5Ca Alloys

Abstract

The microstructure, mechanical properties and corrosion behavior of hot–rolled Mg–xSn–1Zn–0.5Ca (x = 1, 3 and 5 wt.%) alloys were investigated for possible application as biodegradable implants. The hot–rolled Mg–xSn–1Zn–0.5Ca alloys consisted of α-Mg matrix and Mg2Sn phase. The number of the Mg2Sn particles significantly increased and the grains were gradually refined (14.2 ± 1.5, ~10.7 ± 0.7 and ~6.6 ± 1.1 μm), while the recrystallized fraction significantly decreased with the increase in the Sn content, the Mg–1Sn–1Zn–0.5Ca alloy was almost completely recrystallized. Ultimate tensile strength (UTS) and tensile yield strength (TYS) increased slightly, reaching maximum values of 247 MPa and 116 MPa, respectively, for the Mg–5Sn–1Zn–0.5Ca alloy, and the elongation decreased with the increase in the Sn content; the Mg–1Sn–1Zn–0.5Ca alloy showed the highest elongation (15.3%). In addition, immersion tests and electrochemical measurements in Hank’s solution revealed that the corrosion rates of Mg–xSn–1Zn–0.5Ca alloys increased with the increase in the Sn content. A model of the corrosion behavior was discussed for hot–rolled Mg–xSn–1Zn–0.5Ca alloys in Hank’s solution. Among the Mg–xSn–1Zn–0.5Ca (x = 1, 3 and 5 wt.%) alloys, Mg–1Sn–1Zn–0.5Ca alloy exhibits optimal corrosion resistance and appropriate mechanical properties.

In Vitro and In Vivo Testing of Zinc as a Biodegradable Material for Stents Fabricated by Photo-Chemical Etching

“…Mg has the highest corrosion rate, which could negatively affect tissues by releasing too much hydrogen and, because of this, the mechanical integrity of the stents can be compromised prior to the time needed for tissue repair. Pure Zn exhibits a high chemical activity, with an electrode potential of -0.762 V (SHE), which falls between that of magnesium at -2.372 V (SHE) and iron -0.44 V (SHE) [6,7]. Because Zn has a less negative potential compared to Mg, this reduces the chances of forming Zn 2+ compared to the formation of Mg 2+ .…”

Estimation of mechanical properties of Mg-5Zn-0.5Al-xSn alloy based on virtual crystal approximation

“…Therefore, the calculation shows that the content of Sn is related to the mechanical properties of Mg-Zn-Al-Sn alloy, and the research of Ref. [29] , [30] also proves this.…”

Research Progress on Corrosion Resistance of Magnesium Alloys with Bio-inspired Water-repellent Properties: A Review

“…Therefore, the corrosion resistance of the substrate is the key to determining the corrosion behavior of the entire alloy. Researchers analyzed the factors affecting the corrosion of magnesium alloy, and improved the corrosion resistance of magnesium alloy by a number of measures including adding alloy elements [67][68][69][70][71] , reducing the size of the second phase and making the distribution uniform [72][73][74][75][76] , refining the grains [77][78][79][80][81] , changing the crystal orientation and texture strength [82][83][84][85][86] as well as reducing crystal defects [87][88][89] (Fig. 2).…”