期刊
出版社
ELSEVIER
DOI: 10.1016/j.msec.2020.111172
关键词
Zn-based alloys; Biodegradable; Anti-aging; Strain hardening; Degradation
资金
- National Key Research and Development Program of China [2018YFE0115400]
- Natural Science Foundation of China [51971134]
- Shanghai Rising-Star program [19QB1400400]
- Science and Technology Commission of Shanghai Municipality [17XD1402100]
- Shanghai Jiao Tong University Medial-Engineering Cross Fund [ZH2018ZDA34, YG2019ZDA02, ZH2018QNA60]
Zn and its alloys are considered as a new class of biodegradable metals due to their moderate degradation rates and acceptable biocompatibility. However, inadequate mechanical properties limit their further applications, especially for cardiovascular stents. In this study, a novel biodegradable Zn-1.5Cu-1.5Ag (wt%) alloy with excellent mechanical properties was developed, and then its in vitro degradation and cytotoxicity were characterized. Microstructural characterization showed that hot extrusion produced a bimodal distribution of grain size and much finer secondary phase precipitates. The as-extruded alloy exhibited a satisfactory combination of strength and plasticity (yield strength: 162.0 +/- 2.94 MPa, ultimate tensile strength: 220.3 +/- 1.70 MPa and elongation: 44.13 +/- 1.09%). After being aged at room temperature for 8 months, its mechanical properties increased about 10%, implying its good anti-aging ability. The strain hardening exponent (n) calculated from true stress-strain curve showed that this alloy has evident strain hardening. Immersion tests in c-SBF solution revealed that this alloy has a moderate corrosion rate (48.6 +/- 4.14 mu m/year) and slightly localized corrosion behavior. Electrochemical tests showed that a weak passive film formed on surface during degradation, which has a limited protective effect. The cytotoxicity tests exhibited that this alloy possesses acceptable in vitro biocompatibility, which is comparable to pure Zn. According to the results of mechanical properties, corrosion behavior and cytotoxicity, the Zn-1.5Cu-1.5Ag alloy can be regarded as a potential candidate for cardiovascular stent applications.
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