Fabrication and characterization of a biodegradable Mg-2Zn-0.5Ca/1β-TCP composite.
Fabrication and characterization of a biodegradable Mg-2Zn-0.5Ca/1β-TCP composite.
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DOI：
10.1016/j.msec.2015.05.035
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发表时间：
2015-09
期刊：
影响因子：
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通讯作者：
Y. Huang;D. Liu;L. Anguilano;C. You;Minfang Chen
中科院分区：
文献类型：
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作者：
Y. Huang;D. Liu;L. Anguilano;C. You;Minfang Chen
一种可生物降解的镁基β-磷酸三钙（β-TCP）颗粒增强Mg-2 Zn-0.5Ca/1beta-TCP（wt.%）复合材料，通过高剪切凝固（HSS）和等通道转角挤压（ECAE）相结合的新方法制备了生物医用材料。铸态复合材料具有细小的等轴晶组织，β-TCP颗粒均匀分布于2-25 μm的聚集体中。在300 °C下的ECAE处理导致进一步的显微组织细化和β-TCP颗粒分布的改善。在ECAE过程中，β-TCP聚集体被破碎成更小的或单个的颗粒，在基体中形成分散体。这种制造的复合材料表现出增强的硬度和体外耐腐蚀性。β-TCP颗粒的加入和晶粒的细化共同提高了合金的硬度，而腐蚀过程中β-TCP表面形成的富Ca-P层是合金耐蚀性提高的主要原因。该复合材料的特点是在制造过程中，机械性能和电化学性能的极化和浸泡在模拟体液中的测试过程中的微观结构演变。讨论了高速钢和ECAE的优点以及提高耐蚀性的机理。
A biodegradable magnesium matrix and beta-tricalcium phosphate (β-TCP) particles reinforced composite Mg–2Zn–0.5Ca/1beta-TCP (wt.%) was fabricated for biomedical applications by the novel route of combined high shear solidification (HSS) and equal channel angular extrusion (ECAE). The as-cast composite obtained by HSS showed a fine and equiaxed grain structure with globally uniformly distributed β-TCP particles in aggregates of 2–25 μm in size. The ECAE processing at 300 °C resulted in further microstructural refinement and the improvement of β-TCP particle distribution. During ECAE, the β-TCP aggregates were broken into smaller ones or individual particles, forming a dispersion in the matrix. Such fabricated composite exhibited enhanced hardness and in vitro corrosion resistance. The enhanced hardness was attributed to both the addition of β-TCP particles and grain refinement while the development of a Ca–P rich surface layer from β-TCP during corrosion was responsible for the improvement in corrosion resistance. The composite was characterized in terms of microstructural evolution during fabrication, mechanical properties and electrochemical performance during polarization and immersion tests in a simulated body fluid. Discussions are made on the benefits of both HSS and ECAE and the mechanisms responsible for the enhanced corrosion resistance.