Effect of trace HA on microstructure,mechanical properties and corrosion behavior of Mg-2Zn-0.5Sr alloy |
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Authors: | Jian-Xing Li Yuan Zhang Jing-Yuan Li Jian-Xin Xie |
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Affiliation: | 1. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China;2. Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083, China |
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Abstract: | Effect of the addition of trace HA particles into Mg-2Zn-0.5Sr on microstructure, mechanical properties, and bio-corrosion behavior was investigated in comparison with pure Mg. Microstructures of the Mg-2Zn-0.5Sr-xHA composites (x = 0, 0.1 and 0.3 wt%) were characterized by optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD). Results of tensile tests at room temperature show that yield strength (YS) of Mg-2Zn-0.5Sr/HA composites increases significantly, but the ultimate tensile strength (UTS) and elongation decrease with the addition of HA particles from 0 up to 0.3 wt%. Bio-corrosion behavior was investigated by immersion tests and electrochemical tests. Electrochemical tests show that corrosion potential (Ecorr) of Mg-2Zn-0.5Sr/HA composites significantly shifts toward nobler direction from ?1724 to ?1660 mVSCE and the corrosion current density decreases from 479.8 to 280.8 μA cm?2 with the addition of HA particles. Immersion tests show that average corrosion rate of Mg-2Zn-0.5Sr/HA composites decreases from 11.7 to 9.1 mm/year with the addition of HA particles from 0 wt% up to 0.3 wt%. Both microstructure and mechanical properties can be attributed to grain refinement and mechanical bonding of HA particles with second phases and α-Mg matrix. Bio-corrosion behavior can be attributed to grain refinement and the formation of a stable and dense CaHPO4 protective film due to the adsorption of Ca2+ on HA particles. Our analysis shows that the Mg-2Zn-0.5Sr/0.3HA with good strength and corrosion resistance can be a good material candidate for biomedical applications. |
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Keywords: | Magnesium alloys Bio-composites Hydroxyapatite Microstructure Mechanical property Bio-corrosion behavior |
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