低弹性模量Y2O3/TNTZ医用β型钛合金疲劳强度提高机理

How to improve the fatigue strength of β type titanium alloy while keeping low Young's modulus is currently the prospective subject which is urgent to be solved in biomaterial fields. Y2O3 will be added to βtype TNTZ alloy. By means of scanning electron microscope (SEM), transmission electron microscope (TEM), electro probe microanalyzer (EPMA) and other analysis method, the changes of Y2O3 in shape、size、 distribution and so on with the amount of Y2O3 will be observed and analysed. The interface type and characteristic between Y2O3 and the matrix will be studied. The effect of Y2O3 on the fatigue crack initiation and propogation behavior are also to be explored. The interaction mechanism between Y2O3 and the dislocations will be clarified from the micro level. The relationship between Y2O3 and the crack propogation behavior will also be discussed. Thus the improvement mechanism of Y2O3 (shanpe, size, distribution, amount)on fatigue strength of Y2O3/TNTZ alloy can be cleared, and the corresponding physical model will be constructed. The results received in this work are not only expected to provide a new thought for the preparation of low elastic modulus and high fatigue strength ofβtype medical titanium alloy, but also enrich the connotation of fatigue damage mechanism of β type medical titanium alloy, and provide theoretical basis and technical support for the development of new βtype Ti alloy with low Young's modulus and high fatigue strength.

维持医用β型钛合金低弹性模量的同时，提高其疲劳强度，是目前生物材料领域亟待解决的前瞻性课题。本申请针对医用β型TNTZ合金中添加Y2O3，借助扫描显微镜（SEM）、透射电子显微镜（TEM）、电子探针（EPMA）等测试分析手段，系统研究合金中Y2O3形状、尺寸、分布等随Y2O3添加量的变化规律，考察Y2O3与基体之间界面的类型及微观特征，探讨Y2O3对疲劳裂纹萌生和扩展行为的影响规律，从微观层次解析Y2O3与位错交互作用机制，揭示Y2O3与疲劳裂纹扩展行为之间的关系，阐明Y2O3（形状、尺寸、分布、数量）提高Y2O3/TNTZ钛合金疲劳强度的机理，并构建相应的物理模型。 该申请项目所获得的成果不仅能够为制备低弹性模量高疲劳强度医用β型钛合金提供新的思路，而且丰富了医用β型钛合金疲劳损伤机理研究的内涵，并为开发低弹性模量高疲劳强度新型医用β型钛合金奠定理论基础和提供技术支撑。

β钛合金以良好的生物相容性和低弹性模量成为医用材料之首选，然而随着合金弹性模量降低，疲劳强度通常随之下降，因而追求低弹性模量的同时大幅提高β钛合金的疲劳强度成为医用材料领域亟待解决的重要课题之一。本研究在β型TNTZ合金中采用添加Y2O3强化相的方法，旨在维持低弹性模量基本的同时，改善合金的疲劳强度。系统研究了TNTZ合金中Y2O3形状、尺寸、分布等随Y2O3添加量的变化规律，考察Y2O3与基体之间界面的类型及微观特征，探讨Y2O3对疲劳裂纹萌生和扩展行为的影响规律，从微观层次解析Y2O3与位错交互作用机制，揭示Y2O3与疲劳裂纹扩展行为之间的关系，阐明Y2O3（形状、尺寸、分布、数量）提高Y2O3/TNTZ钛合金疲劳强度的机理，并构建相应的物理模型。研究结果不仅能够为制备低弹性模量高疲劳强度医用β型钛合金提供新的思路，而且丰富了医用β型钛合金疲劳损伤机理研究的内涵，并为开发低弹性模量高疲劳强度新型医用β型钛合金奠定理论基础和提供技术支撑。