高强度原位自生超细晶双相钛合金的制备及其在生物医疗领域的应用

PREPARATION OF HIGH-STRENGTH IN SITU ULTRAFINE GRAINED DUAL PHASE TITANIUM ALLOYS FOR BIOMEDICAL APPLICATION

张亦文

11649145

硕士

材料工程

任富增

2018-05-20

2018-07-03

哈尔滨工业大学

深圳

钛合金由于其出色的耐腐蚀性能及生物相容性在骨植入领域得到了广泛的应用，常被应用于人工骨、人工关节、人工脊柱、骨板、牙种植体等硬组织替代材料。然而常见的医用钛合金包括纯钛在临床使用中都存在着一些问题，例如 Ti-6Al-4V 中的 Al 和 V 离子溶出可能对人体产生有害作用，纯钛的强度较低、熔点较高不利于成型等。虽然钛合金通常拥有较好的生物相容性，但其抗菌性能仍然有待改善。通过铸造、真空电弧熔炼等传统方法通常只能制备大晶粒尺寸的材料，通过细化晶粒来提高其性能的后续处理工序繁琐。基于提高力学性能以及抗菌性能的考虑，提出了在 Ti-Mo 合金体系中加入抗菌元素 Ag 的实验设计。本课题基于高能球磨（机械合金化）与放电等离子体烧结（SPS）相结合的方法，通过控制烧结参数制备了两种不同组织结构的超细晶双相 Ti-5Mo-5Ag 合金，采用 X 射线衍射分析、扫描电子显微观察、压缩实验、摩擦实验、电化学实验、抗菌实验、离子释放实验、体外细胞相容性评价实验研究了不同温度烧结的 Ti-5Mo-5Ag 合金的微观结构、力学性能、抗腐蚀性能、抗菌性能、生物相容性，主要考察了两相结构的相分布、晶粒尺寸对力学行为的影响，此外还考察了 Ti-5Mo-5Ag 合金应用于生物医疗领域的可行性。论文取得了如下研究成果：设计并制备了 Ti-5Mo-5Ag 超细晶双相合金，烧结温度 800 ℃时得到等轴组织，烧结温度 900 ℃时得到双态组织。压缩实验表明两种不同组织形态的 Ti-5Mo-5Ag 试样都具有较高的压缩强度，其中等轴组织的合金具有较好的塑性，双态组织的合金具有更高的强度。同时，Ti-5Mo-5Ag 合金的耐腐蚀性能优于纯钛，双态组织 Ti-5Mo-5Ag 合金具有更好的耐腐蚀性能，但是耐磨损性能有待改善。通过将金黄色葡萄球菌与样品共培养的方式研究了双相 Ti-5Mo-5Ag 合金的抗菌性能，结果表明，双态组织的抗菌率高于 95%，等轴组织的 Ti-5Mo-5Ag合金抗菌性较差。Ti-5Mo-5Ag 合金主要通过 Ag+离子的溶出达到抗菌效果。采用小鼠成骨细胞 MC3T3-E1 研究了 Ti-5Mo-5Ag 合金的生物相容性，细胞黏附实验结果表明 Ti-5Mo-5Ag 合金具有良好的生物相容性，细胞增殖未受到抑制，同时利用激光共聚焦显微镜和扫描电镜观察得到了样品表面不同黏附时间的细胞活死状态及细胞形态。实验结果表明，样品具有与纯钛相当的生物相容性。综上所述，本文制备了一种新型医用超细晶双相钛合金，对其进行组织结构调控获得了较好的力学性能、耐腐蚀性能，同时可以达到较高的抗菌率以及较好的生物相容性，为钛合金在生物医疗领域的应用提供了新的选择。

Titanium alloys have been widely used in hard tissue alternative materials due to their excellent corrosion resistance and biocompatibility, such as artificial bones, artificial joints, artificial spines, bone plates, dental implants, etc. Howeve r, the commonly used medical titanium alloys, including pure titanium, have some problems in clinical practice. For example, the release of Al and V ions in Ti-6Al-4V may have toxic effects. Commercially pure titanium has low strength and the high melting point also causes casting issues. In addition, although titanium alloys generally have good biocompatibility, their antibacterial properties still need to be improved. At the same time, titanium alloys fabricated by conventional methods such as casting and vacuum arc melting usually have coarse grains, and the subsequent processing steps to refine the grain size to improve their performance are cumbersome. In order to increase the mechanical properties and anti-bacterial ability, we aimed to add Ag into Ti-Mo system.In this project, we have combined high energy ball milling (mechanical alloying) and spark plasma sintering to fabricate two kinds of ultrafine grained Ti-5Mo-5Ag alloys with different microstructures by controlling sintering parameters. Scanning electron microscopy, uniaxial compression, pin-on-disk wear tests, electrochemical corrosion tests, antibacterial activity evaluation, ion release, and in vitro cell culture experiments have been performed to study the microstructure, mechanical properties, corrosion and wear resistance, antibacterial properties and cytocompatibility of Ti-5Mo-5Ag alloys sintered at different temperatures. The main conclusions reached from the present thesis are summarized as below:1) Ultrafine grained Ti-5Mo-5Ag dual phase alloys with different phase distributions have been successfully prepared. The equiaxed structure was gained through sintering below β-phase transition temperature and the duplex macrostructure was gained through sintering above β-phase transition temperature.2) Uniaxial compression experiments show that both the Ti-5Mo-5Ag alloys show high compressive strength. In particular, the alloy with equiaxed microstructure have better ductility and the alloy with the duplex microstructure demonstrates higher strength. 3) The corrosion resistance of Ti-5Mo-5Ag alloys are better than that of pure titanium, and the alloy with duplex microstructure has better corrosion resistance, but the wear resistance of the present Ti-5Mo-5Ag needs to beimproved.4) The antibacterial property of the Ti-5Mo-5Ag alloys has been studied by co_x005f cultivating Staphylococcus aureus and the samples. The results show that th eTi-5Mo-5Ag alloy with duplex microstructure has superior antibacterial The calculated antibacterial rate reaches 95%. The equiaxed tissue has poor antibacterial properties. The antibacterial effect the Ti-5Mo-5Ag alloys areattributed to the release of Ag+ions.5) The mouse osteoblasts MC3T3-E1 was adapted for cell adhesion experiments. The Ti-5Mo-5Ag alloy shows good biocompatibility. The cells adhered on the surface of Ti-5Mo-5Ag alloy was not affected by the released Ag+iron. The statues of osteoblasts were observed by SEM and laser scanning confocal microscopy(LSCM).The good biocompatibility of the Ti-5Mo-5Ag alloy was certificated by the Experimental results.In summary, we fabricated a new kind of high-strength in situ ultrafine grained dual phase titanium alloys and the samples shows great mechanical properties, excellent corrosion resistance, high antibacterial rate and good biocompatibility. It provides a new choice of titanium alloys for biomedical applications

钛合金 高能球磨 放电等离子体烧结 力学性能 抗菌性能 生物医用金属

titanium alloy high energy ball milling spark plasma sintering mechanical properties antibacterial properties biomedical metals

中文

联合培养

南方科技大学

张亦文. 高强度原位自生超细晶双相钛合金的制备及其在生物医疗领域的应用[D]. 深圳. 哈尔滨工业大学,2018.