镁合金接骨板的力学性能与微动磨损特性研究

发布时间：2018-02-11 12:54

本文关键词： 金属接骨板可降解镁合金微弧氧化力学性能微动磨损　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着骨折内固定技术的发展,接骨板在临床上得到广泛应用。一方面,现阶段用于骨折坚强内固定的接骨板材料多为不锈钢、钛及钛合金等具有高弹性模量的生物惰性金属。然而,这些传统接骨板的结构刚度较高,不仅会导致应力遮挡,而且阻碍骨折块间形成适当的轴向位移,不利于骨折愈合。此外,生物惰性金属接骨板在骨折愈合后需要手术取出,给患者带来额外痛苦。鉴于镁合金不仅具有良好的机械性能,而且可在生物体内无毒降解,因此,生物可降解镁合金在骨折内固定器械方面具有广阔的应用前景。现有研究主要关注镁合金在生物体内的降解行为、对骨折修复的影响及其生物相容性等。实际上,镁合金接骨板—骨折系统良好的机械性能是保证骨折有效愈合的重要因素,但这方面的研究目前尚未见系统报道。因此,很有必要开展镁合金接骨板机械性能的研究,研究结果有助于促进镁合金在骨折内固定中的临床应用。本论文利用力学测试平台,对比研究了挤压态ZK60镁合金和TA3纯钛接骨板固定股骨干不稳定骨折时的力学性能;并采用微弧氧化处理在ZK60镁合金表面制备了不同的微弧氧化陶瓷层,采用体外微动模拟试验,考察了 ZK60镁合金试样在接骨板服役工况下的微动磨损行为,揭示了电压、占空比等微弧氧化电参数对ZK60镁合金表面微动磨损性能的影响规律。主要结果与结论如下:(1)ZK60镁合金接骨板固定股骨干不稳定型骨折时具有较低的静态结构刚度,更趋于弹性固定从而有助于减小应力遮挡作用,它不仅能在骨折初期有效承载,还能确保骨折块间具有足够的轴向位移以刺激骨痂形成,其骨折愈合性能优于TA3纯钛接骨板。然而,ZK60接骨板—骨折结构的静态强度和轴向载荷下的疲劳强度均低于TA3接骨板。(2)ZK60表面的微弧氧化层能显著提高其在接骨板服役工况下的耐腐蚀性能,试样表面的腐蚀电流密度及腐蚀速率均明显降低。(3)微弧氧化处理能显著提高ZK60镁合金表面在接骨板服役工况下的耐微动磨损性能,微弧氧化电压对其具有显著影响,不同脉冲占空比则无显著影响。随电压升高,微弧氧化ZK60在模拟体液中的耐微动磨损性能先增后减,最佳电压为350 V。
[Abstract]:With the development of fracture internal fixation technology, bone plate has been widely used in clinic. On the one hand, most of the materials used for internal fixation of fracture are stainless steel. Titanium and titanium alloys are biologically inert metals with high modulus of elasticity. However, the structural stiffness of these traditional plates is relatively high, which not only leads to stress occlusion, but also hinders the formation of proper axial displacement between fracture fragments. In addition, biological inert metal plates need to be surgically removed after fracture healing, causing additional pain to patients. Since magnesium alloys not only have good mechanical properties, but also can be detoxified in organisms, so, Biodegradable magnesium alloys have a broad application prospect in fracture internal fixation devices. The current research focuses on the biodegradation behavior of magnesium alloys in vivo, the effects on fracture repair and their biocompatibility. The good mechanical properties of the magnesium alloy plate fracture system is an important factor to ensure the effective healing of the fracture, but the research on this aspect has not been systematically reported. Therefore, it is necessary to study the mechanical properties of the magnesium alloy bone plate. The results are helpful to promote the clinical application of magnesium alloy in fracture internal fixation. In this paper, the mechanical properties of extruded ZK60 magnesium alloy and TA3 pure titanium plate were compared with each other in the treatment of unstable femoral shaft fracture. Different micro-arc oxidation ceramic coatings were prepared on the surface of ZK60 magnesium alloy by micro-arc oxidation. The fretting wear behavior of ZK60 magnesium alloy under service condition was investigated by in vitro fretting simulation test, and the voltage was revealed. The effect of duty cycle on the fretting wear properties of ZK60 magnesium alloy surface is studied. The main results and conclusions are as follows: 1 / 1 mg alloy plate fixation of unstable femoral shaft fracture has low static structural stiffness. More elastic fixation helps reduce stress occlusion, not only in the early stages of the fracture, but also in ensuring that there is enough axial displacement between the pieces to stimulate callus formation. The fracture healing performance of ZK60 is better than that of pure titanium TA3 plate. However, the static strength and fatigue strength of ZK60 plate under axial load are lower than that of TA3 plate. Corrosion resistance under service conditions, The corrosion current density and corrosion rate on the surface of the ZK60 magnesium alloy decreased significantly. The micro-arc oxidation treatment could significantly improve the fretting wear resistance of the surface of ZK60 magnesium alloy under the service condition of the bone-plate, and the micro-arc oxidation voltage had a significant effect on the micro-arc oxidation. With the increase of voltage, the fretting wear resistance of ZK60 in simulated body fluid increased first and then decreased, and the optimum voltage was 350V.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.22;R318.08

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