【作者】 郭仕彪；

【导师】 刘江南；

【作者基本信息】 西安工业大学 ， 材料物理与化学， 2012， 硕士

【摘要】 镁合金具有密度小、弹性模量小和比刚度高等特点,其综合力学性能与人体骨骼相近。同时,镁具有良好的生物相容性,镁离子是一种人体必需的营养素,因此镁合金作为生物材料具有很好的发展前景。镁合金较差的抗腐蚀性能为医学领域对可降解生物金属材料的开发提供了思路：将镁合金冠脉支架或骨钉植入人体后,镁合金会随植入部位的痊愈而降解消失。本文对Mg-RE-1.0Zr合金的铸态、固溶态和固溶+时效态三种状态,利用失重法在人体模拟Hank溶液中进行单、双边模拟腐蚀试验,测定腐蚀速率,分析合金的腐蚀动力学特征及其影响因素。通过SEM扫描,观察腐蚀后的微观形貌,分析腐蚀机理。另外,对生物镁合金支架的设计和加工进行了探讨。试验结果表明：Mg-RE-1.0Zr铸态、固溶态与固溶+时效态试样双边腐蚀的平均动态腐蚀速率分别为0.8848mg/(cm2·h)、0.1363mg/(cm2·h)和0.1445mg/(cm2·h),平均静态腐蚀速率分别为0.5841mg/(cm2·h)、0.0969mg/(cm2·h)和0.1046mg/(cm2·h)。腐蚀过程都是一个从快到慢,最后趋于平稳的过程,动态腐蚀速率要大于静态腐蚀速率,腐蚀动力学关系符合负指数特征。与支架在人体冠状动脉中情况更为相近的单边模拟腐蚀中,固溶+时效态试样的平均腐蚀速率为0.1917 mg/(cm2·h),在168h后试样的腐蚀速率趋于平稳在0.0688 mg/(cm2·h)左右,腐蚀速率大于双面腐蚀。通过扫描电镜观察,发现未经压缩的试样以晶界腐蚀为主,压缩后的固溶+时效态试样的腐蚀形态为点蚀。对380℃压缩变形的Mg-RE-1.0Zr固溶+时效态试样的再结晶行为进行了研究,确定Mg-RE-1.0Zr的再结晶退火温度为350℃。更多还原

【Abstract】 Magnesium alloys have the character of low density, low modulus of elasticity and high specific stiffness, and its mechanical properties are close to the human skeleton. Magnesium has excellent biocompatibility and is an essential nutrient element for human. So it has good prospects as the biological material. Poor corrosion resistance of magnesium alloys provide a guideline for the development of biodegradable metallic materials in the medical field. As coronary stents or bone screws implanted in the human body and magnesium alloy degradably disappears with the healing of the implant site.The corrosion rate, corrosion kinetic characteristics and their impact factors of Mg-RE-l.OZr alloy as casting, solid solution state and solid solution+aging state are studied by single and bilateral corrosion test in simulated body Hank solution by using of weight loss method. The corrosion morphology is observed by scanning electron microscopy and the corrosion mechanism is analyzed. Moreover, the design and processing of the biological magnesium alloy stent have been disscussed.The results show that the average dynamic corrosion rate of Mg-RE-1.0Zr with casting state, solid solution state and solid solution+aging state specimen are 0.8848mg/(cm2·h), 0.1363mg/(cm2-h) and 0.1445mg/(cm2-h) measured by bilateral corrosion test. The average static corrosion rate are 0.5841mg/(cm2·h),0.0969mg/(cm2-h) and 0.1046mg/(cm2-h). At first, the corrosion speed obviously decreases with the corrosion time and finally tends to be stable. The dynamic corrosion rate is greater than that of the static corrosion rate. The unilateral simulation corrosion behavior is similar to that of the stent in human coronary artery and the corresponding average corrosion rate of solid solution+aging state is 0.1917 mg/(cm·h) and the corrosion rate is about 0.0688 mg/(cm2·h) after 168h corrosion. The unilateral corrosion rate is greater than that of the double-sided corrosion. The corrosion mechanism of the no-compression specimen grain is boundary corrosion and the pitting is the corrosion mechanism of the compressed specimen with solid solution+aging state.The recrystallization behavior of Mg-RE-1.0Zr specimens in solid solution+aging state compressed have been investigated and the recrystallization annealing temperature is determined to 350℃.更多还原