低弹性模量高强度多孔钛基金属玻璃的制备及其生物学性能研究

With a continuously increasing aging society and the improvement of quality of life, large demands of the biological and biomedical materials are expected for a long time. Metallic materials are widely used as biomaterials to replace or repair structural components of the human body because of their excellent mechanical properties and reliability. However, the metallic biomaterials currently used for implant applications have two major problems: containing toxic or non-biocompatible elements, and mismatch of elastic modulus between implant and bone. In this study, we will develop porous Ti-based bulk metallic glasses simultaneously with large size, high strength, low elastic modulus similar to natural bone, and excellent biocompatibility by using spark plasma sintering (SPS) process. The main contents of the study include: (1) to understand the sintering process and sintering mechanism of SPS, establish the optimum process conditions for the preparation of Ti-based metallic glass powders and the SPS sintering process; (2) to study microstructure, physical, chemical and mechanical properties of porous materials; (3) to evaluate corrosion behavior and in vitro osteoblast response under simulated biological environment conditions, as well as in vivo biological properties. The success of this project is expected to open up an effective way to develop high performance biomedical materials. Not only push forward application of metallic glasses as biomedical materials, but also promote interdisciplinary development of materials science, metallurgy and biotechnology fields.

针对目前使用的生物医用金属材料中含生物有害元素、与人骨弹性模量不匹配的问题，本申请提出利用仅由高生物相容性金属元素组成的钛基金属玻璃粉作为出发原料，采用放电等离子体烧结(SPS)工艺制备出同时兼备优秀生物相容性、具有人骨同程度弹性模量和高强度的多孔钛基生物用金属玻璃材料。研究内容主要包括：(1)阐明SPS的烧结过程及其烧结机理，确立制备钛基金属玻璃粉以及SPS烧结的最佳工艺条件；(2)研究多孔样品的微观组织、物理化学性能和机械性能；(3)评价其在模拟生物环境条件下的腐蚀行为以及体外、体内的生物相容性和生物安全性。本项目研究成功，可望开拓一条制备高性能生物医用材料的有效途径，不仅对推动金属玻璃作为生物医疗材料的实用化进程具有重大现实意义，而且将促进材料科学、冶金学和生物技术等学科的相互交叉渗透发展，丰富相关研究领域的基础理论，具有重大学术价值。

本项目针对传统钛合金含有V、Ni生物毒性元素和高弹性模量等弊端开发了无毒、低弹性模量的多孔钛基金属玻璃合金。设计并制备了不含Be、Ni等生物有毒有害元素Ti-Zr-Cu-Pd-Sn金属玻璃合金粉末，利用占位填料法，结合放电等离子体烧结技术来实现粉末固结。探究了烧结过程中热力学参数对材料的影响，以实现不同孔隙率材料的制备。结果表明，随着烧结温度的升高，材料的杨氏模量和抗压强度随孔隙率的降低而减小，当多孔材料的孔隙率为21-24%时，力学性能和人骨相匹配。对材料在模拟生物环境条件下的腐蚀特性进行了评价，电化学动电位极化曲线测试以及阻抗测试证实了通过调控放电等离子烧结工艺向钛基金属玻璃中引入多孔结构，并不会造成材料耐腐蚀性能的显著下降，其耐腐蚀性能大幅度优于商用钛基生物材料（Ti-6Al-4V）。生物模拟体液中浸泡实验以及细胞增殖实验显示多孔结构的引入并不会破坏钛基金属玻璃的耐腐蚀性以及细胞安全性。体内植入试验结果表明，多孔钛基金属玻璃骨植入物显示其具有优异的生物相容性，骨整合和粘结能力与对照样品（纯钛）相当。.在不含Be、Ni等生物有毒有害元素的前提下，为了降低钛基金属玻璃的制备成本，本项目开发了低成本Ti-Fe-Si和Ti-Zr-Si金属玻璃合金。采用熔炼-金属液体急冷技术制备带材，确定了Ti-Fe-Si金属玻璃成分，利用放电等离子体烧结技术制备了力学性能与人骨匹配的大尺寸多孔Ti-Fe-Si块状金属玻璃，弹性模量仅为27.7 GPa。利用机械合金化工艺结合放电等离子体烧结技术制备新型Ti-Zr-Si大块金属玻璃，研究了制备工艺对材料力学性能的影响，获得了断裂强度为385 MPa，杨氏模量为55 GPa的大块Ti-Fe-Si金属玻璃合金。

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