镁基非晶复合材料的协同增塑机制及其生物腐蚀机理研究

Mg-Zn-Ca bulk metallic glasses have the advantages of biodegradable and high strength. Key scientific problems in study on biological applications of Mg-based bulk metallic glasses are the brittle fracture (synergistically enhanced plasticity mechanism) and the rapid degradation (corrosion mechanism). This project proposes to improve the macroscopic plasticity of Mg-Zn-Ca bulk metallic glasses composites by the synergetic effect of the second phase enhanced plasticity and thermal cycle low temperature aging treatment. Synergistically enhanced plasticity mechanism will be investigated by studying the precipitation process, phase distribution, microstructure and the formation and evolution of multiple shear bands in Mg-Zn-Ca bulk metallic glasses composites. The deep causes of pitting corrosion formation, the thermodynamic conditions and kinetic processes of the formation of dense passivation film will be investigated. The mechanism of corrosion failure in simulated body fluids will be revealed. The degradation speed of Mg-Zn-Ca bulk metallic glasses composites will match the rate of fracture recovery or bone tissue reconstruction. The uncontrollable corrosion failure will become controlled corrosion behavior. At the same time, the overall failure of the composites caused by pitting corrosion on the surface will be avoid. The degradation period of Mg-Zn-Ca bulk metallic glasses composites implants will be evaluated and measured.

Mg-Zn-Ca非晶合金作为生物植入材料，兼具可生物降解和较高强度等优点，但脆性断裂（增塑机制）和降解速度过快（腐蚀机理）是阻碍其生物应用的关键科学问题。本项目提出通过第二相增塑和热循环低温老化增塑的协同作用，提高Mg-Zn-Ca非晶复合材料的宏观塑性。通过研究Mg-Zn-Ca非晶复合材料中相的析出过程、相的分布特征、微观结构、形变过程中多重剪切带的形成及演化行为，揭示协同作用下Mg-Zn-Ca非晶复合材料双重增塑机制。通过系统研究Mg-Zn-Ca非晶复合材料发生点蚀的深层次原因、以及致密性钝化膜形成的热力学条件和动力学过程揭示其在模拟体液中的腐蚀失效机理，使其降解速率与骨折痊愈速度或骨组织重建速度相匹配，将不可控的腐蚀失效变成可以调控的腐蚀行为；同时，避免复合材料表面点蚀引起的材料整体失效的发生，从而实现可以评价和测算植入物的降解周期。

Mg-Zn-Ca非晶合金作为生物植入材料，兼具可生物降解和较高强度等优点，但脆性断裂（增塑机制）和降解速度过快（腐蚀机理）是阻碍其生物应用的关键科学问题。本项目提出了通过复合增塑和热循环低温老化增塑的协同作用，通过研究Mg基非晶复合材料中相的析出过程、相的分布特征、微观结构、形变过程中多重剪切带的形成及演化行为，揭示了协同作用下Mg基非晶复合材料双重增塑机制，提高了Mg基非晶复合材料的宏观塑性。利用合金元素的成分设计、析出相体积分数的控制，以及设计Mg基非晶复合材料表面的致密性保护膜层，揭示Mg基非晶复合材料的腐蚀机理，提高Mg基非晶复合材料的耐腐蚀性能。本研究不仅具有重要的学术价值，而且将为Mg基非晶合金的实际应用提供依据。