生物医用Ti-Sn涂覆层合金的制备及其摩擦性能研究

发布时间：2018-10-26 09:49

【摘要】：新型β钛基形状记忆合金Ti-7.5Nb-4Mo-2Sn由于具有较低的弹性模量、优异的超弹性能、良好的生物相容性和耐腐蚀性,在生物医用植入材料方面具有广泛的应用前景。为了改善该合金表面硬度低、耐磨性能差的问题,本文进行了涂覆层合金成分设计,开发和制备了Ti-xSn系列合金,研究了Sn含量对Ti-Sn合金显微组织和耐磨性能的影响。然后选取性能最优的Ti-Sn合金,以预置薄片的方式通过激光熔覆制备得到Ti-Sn涂层,并对不同扫描速度下表面改性层的组织、硬度、温度场分布、表面耐磨性能等进行了研究。其主要结论如下:(1)从生物医用熔覆层合金设计角度制备了Ti-xSn系列合金,研究了Sn含量对Ti-xSn合金显微组织和耐磨性能的影响。结果表明,当合金中Sn含量从6at.%-20at.%变化时,β相含量和合金表面硬度与耐磨性能直接相关联,即β相含量少,硬度高、耐磨性好。其中以Ti-10Sn表面硬度最高,耐磨性能最好。(2)成功在Ti-7.5Nb-4Mo-2Sn合金表面激光熔覆制备Ti-10Sn涂层,基体与涂层获得冶金结合且连接界面无明显孔洞和缺陷,表面硬度和耐磨性能得到明显提高。且基体和涂层的磨损机制不一致,基体的磨损机制为粘着磨损和磨粒磨损共同作用,而涂层的磨损机制为磨粒磨损。(3)研究了扫描速度对涂层性能的影响。结果表明,在功率和光斑一定的情况下,随着扫描速度的增加,冷却速率加快,涂层与基体连接界面的温度降低。基于硬度和耐磨性能研究,得出10mm/s时涂层耐磨性能最好。三种不同扫描速度下得到的涂层磨损机制不同,扫描速度为13mm/s时涂层为粘着磨损与磨粒磨损共同作用机制,10mm/s时为典型的磨粒磨损机制,而7mm/s时表面磨损机制进一步发生了改变,表面出现裂纹,为疲劳磨损。
[Abstract]:The new 尾 -titanium-based shape memory alloy (Ti-7.5Nb-4Mo-2Sn) has been widely used in biomedical implants due to its low elastic modulus, excellent hyperelastic properties, good biocompatibility and corrosion resistance. In order to improve the low surface hardness and poor wear resistance of the alloy, the composition design of the coated alloy was carried out, and the Ti-xSn series alloys were developed and prepared. The effect of Sn content on the microstructure and wear resistance of the Ti-Sn alloy was studied. Then the Ti-Sn alloy with the best performance is selected and the Ti-Sn coating is prepared by laser cladding in the form of preset wafer. The microstructure, hardness and temperature field of the surface modified layer are obtained at different scanning speeds. The surface wear resistance was studied. The main conclusions are as follows: (1) the effects of Sn content on microstructure and wear resistance of Ti-xSn alloy were studied from the point of view of design of biomedical cladding alloy. The results show that when the content of Sn in the alloy changes from 6at.to -20at.%, the content of 尾 phase and the hardness of the alloy surface are directly related to the wear resistance, that is, the content of 尾 phase is low, the hardness is high, and the wear resistance is good. The surface hardness of Ti-10Sn is the highest and the wear resistance is the best. (2) the laser cladding of Ti-10Sn coating is successfully made on the surface of Ti-7.5Nb-4Mo-2Sn alloy, and the metallurgical bonding between the substrate and the coating is obtained, and there are no obvious holes and defects in the interface between the substrate and the coating. The surface hardness and wear resistance were improved obviously. The wear mechanism of substrate and coating is different. The wear mechanism of substrate is adhesive wear and abrasive wear, while the wear mechanism of coating is abrasive wear. (3) the effect of scanning speed on the properties of coating is studied. The results show that the cooling rate increases with the increase of the scanning speed and the temperature of the interface between the coating and the substrate decreases with the constant power and spot. Based on the research of hardness and wear resistance, it is concluded that the coating has the best wear resistance when 10mm/s. The wear mechanism of the coating is different at three different scanning speeds. When the scanning speed is 13mm/s, the coating is the joint mechanism of adhesive wear and abrasive wear, and the 10mm/s is the typical abrasive wear mechanism. However, the surface wear mechanism of 7mm/s is changed further, and the surface cracks appear, which is fatigue wear.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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