Dresden 2020 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 51: Computational Materials Modelling - Mechanical Properties
MM 51.4: Talk
Thursday, March 19, 2020, 11:00–11:15, IFW B
Synergetic effects of solute and strain in biocompatible Zn-based and Mg-based alloys — •Shihao Zhang1,2, Yuanqi Guo1, Irene J. Beyerlein3, Dominik Legut2, Shunli Shang4, Zi-Kui Liu4, and Ruifeng Zhang1 — 1School of Mat. Sci. and Eng., Beihang University, China — 2IT4Innovations, VSB-TU Ostrava, Czech Republic — 3University of California at Santa Barbara, USA — 4Pennsylvania State University, USA
Zn and Mg alloys are considered highly promising biodegradable materials for cardiovascular stent applications; however, their poor strength has prevented this application. Via first-principles calculations and Peierls-Nabarro model, we investigate the coupled effect of the solute element and mechanical straining on the stacking fault energy (SFE), dislocation core structure, and Peierls stress in Zn and Mg alloys. Several biocompatible solute, i.e., Li, Al, Mn, Fe, Cu, Mg and Zn, were considered. It is suggested that some elements, like Fe, can potentially enhance strength in both Zn and Mg alloys, while other elements, like Li, can lead to opposed effects. The effect of solute strengthening and longitudinal straining on SFEs is much stronger for the Zn alloys than for the Mg alloys. Investigations on electronic structure and bond lengths reveal a coupled chemical-mechanical effect of solute and strain on electronic polarization, charge transfer, and bonding strength, which can explain the weak mechanical effect on Zn alloys and the variable strengthening effect among these solutes. These findings provide critical information needed in solute selection in Zn and Mg alloy design for biomedical applications.