Effect of solid solution treatment on in vitro degradation rate of as-extruded Mg-Zn-Ag alloys

• Published in: Transactions of Nonferrous Metals Society of China 2017-12, Vol.27 (12), p.2607-2612
• Main Authors: WANG, Li-qing, QIN, Gao-wu, SUN, Shi-neng, REN, Yu-ping, LI, Song
• Format: Article
• Language: English
• Subjects: biodegradable Mg alloy; corrosion resistance; Mg-Zn-Ag alloy; solution treatment
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(17)60288-7

The degradation behaviors of the as-extruded and solution treated Mg-3Zn-xAg (x=0, 1, 3, mass fraction, %) alloys, as well as as-extruded pure Mg, have been investigated by immersion tests in simulated body fluid (SBF) at 37 °C. The as-extruded Mg-Zn(-Ag) alloys contained Mg51Zn20 and Ag17Mg54. While the quasi-single phase Mg-Zn(-Ag) alloys were obtained by solution treatment at 400 °C for 8 h. The quasi-single phase Mg-Zn(-Ag) alloys showed lower degradation rate and more homogeneous degradation than corresponding as-extruded Mg alloys. Degradation rate of solid-solution treated Mg-3Zn-1Ag and Mg-3Zn-3Ag was approximately half that of corresponding as-extruded Mg alloy. Moreover, the degradation rate of solid-solution treated Mg-3Zn and Mg-3Zn-1Ag was equivalent to that of as-extruded pure Mg. However, heterogeneous degradation also occurred in quasi-single phase Mg-Zn-Ag alloys, compared to pure Mg. So, preparing complete single-phase Mg alloys could be a potential and feasible way to improve the corrosion resistance.