Chinese scientists to speak on magnesium alloys and their biodegradability in biomedical devices

Two scientists from the Institute of Metal Research, Chinese Academy of Sciences, will visit the NSF Engineering Research Center for Revolutionizing Metallic Biomaterials at N.C. A&T on Wednesday.  Drs. Jian Xu and Ling-ling Shi will give a presentation followed by discussion and a lab tour. The research institute is one of the leading research centers for biomedical magnesium alloy research in China.

Their talk will begin at 10 a.m. in the Fort Interdisciplinary Research Center, Room 328.

Topic: Biodegradable Mg-Zn-Y alloys with long-period stacking ordered structure for orthopedic applications

Abstract: Due to their degradability in physiological environments, magnesium alloys exhibit significant advantages in promoting bone growth and avoiding secondary surgery. Thus, they are highly expected as new generation of biodegradable orthopedic devices. However, fast degradable rate, hydrogen release and lower strength remain current challenges. Mg-Zn-Y alloys with long period stacking ordered (LPSO) phase were claimed to have high yield strength. Their potential for orthopedic application is investigated from the perspective of mechanical properties and in vitro assessment of biodegradable rate. Ternary Mg100-3x(Zn1Y2)x (x=1, 2, 3) alloys were studied to evaluate the effect of volume fraction of LPSO phase on mechanical properties and degradability. As indicated, volume fraction of the LPSO structure increases with increasing the Zn/Y concentration. It results in an increase of yield strength and decrease in plasticity, together with the promoted degrading in physiological condition. Minor addition of Zr plays a role of grain size refinement. The alloy with Zr exhibits not only higher strength (~165 MPa) but also mitigates the degradable rate.  Half-life time of alloy corrosion measured by in vitro assessment can be used as a parameter to evaluate the degradability of alloy, which scales with electrochemical passivity behavior.

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