新型血管支架用β型Ti-Ta-Hf-Zr合金设计及组织、性能研究

发布时间：2018-03-13 07:00

本文选题：Ti-Ta-Hf-Zr合金　切入点：金属血管支架　出处：《吉林大学》2017年博士论文　论文类型：学位论文

【摘要】：由于钛及其合金具有高的比强度,优异的耐腐蚀性、生物相容性和较低的弹性模量,是生物医用材料研究的热点。生物钛合金除了应用于整形外科、牙科之外,作为心血管支架材料的研究也逐步受到重视。目前,常用的支架材料有金属材料和高分子材料两种,相对高分子材料而言,金属支架性能更加稳定,可以提供更好的支撑强度。316L SS不锈钢是球囊扩张式支架最常用的材料之一,Ni-Ti合金也广泛用作自展式支架材料,然而,它们都含有金属Ni,这会引发局部免疫反应和炎症。因此,亟需一种既能满足支架所需的力学性能、又是生物相容性好的新型材料。本文基于d电子合金设计、平均价电子浓度(e/a)、钼当量(Moeq)等理论设计方法,设计制备出新型血管支架用β型Ti-37Ta-26Hf-13Zr,Ti-40Ta-22Hf-11.7Zr和Ti-45Ta-18.4Hf-10Zr(wt.%)三组性能优异且生物相容性好的合金,并采用光学显微镜、共聚焦显微镜、X射线衍射仪、扫描电镜、透射电镜、显微硬度计、电子万能试验机、电化学工作站、X射线光电子能谱仪等系统分析了铸态合金组织、机械性能、耐腐蚀性能及生物相容性,并采用热处理、热机械成型等方式优化了组织与性能。本文的主要研究工作与结论如下:1、设计的三组Ti-Ta-Hf-Zr铸态合金具有较高的强度(压缩屈服强度,抗拉强度和拉伸屈服强度)、弹性容许应变和显微硬度。优异的机械性能基本满足自扩张支架应用的性能要求。高屈服强度与高弹性容许应变相结合为设计更薄壁厚支架提供了更大可能,以减小金属支架中再狭窄率,但合金的延伸率有待提高。2、固溶时效处理时,随着时效时间的延长Ti-40Ta-22Hf-11.7Zr合金组织变化为:β+ωath→β→β+α"→β+α"+α→β+α+ωiso,合金的强度、硬度随着时效时间的延长而提高,塑性降低。固溶态时,合金显示出优异的压缩性能,压缩屈服强度约为1018 MPa,压缩应变为70%时,仍未压裂。OCP的结果显示,Ti-40Ta-22Hf-11.7Zr在铸态时耐腐蚀性能优于cp-Ti和Ti6Al4V。耐腐蚀性能优异是由于合金表面形成Ti O2、Ta2O5、Hf O2、Zr O2和Zr2O3等钝化膜。3、较低形变量热轧时(20%、60%),Ti-40Ta-22Hf-11.7Zr合金产生应力诱发马氏体α"组织,较大形变量(80%、90%)热轧时,发生动态再结晶,晶粒显著细化,晶粒尺寸由固溶态时的335.3μm降为12.4μm左右。由于位错、细晶强化等因素影响,合金的力学性能较铸态、固溶态有一定的提升。经过再次固溶处理后,组织经历再结晶及晶粒长大的过程,此时强度、硬度、杨氏模量稍有降低,但延伸率、弹性容许应变得到较大的提升。当形变量为90%时,综合性能最优,此时,显微硬度:347.3±8.0 HV,抗拉强度:1272.4±37.6 MPa,屈服强度:1231.8±33.5 MPa,延伸率:9.69±0.26%,杨氏模量:62.9±2.1 Gpa。尤其是弹性容许应变达到1.96±0.05%,媲美以弹性容许应变著称的块状金属玻璃(BMG)。此时,合金的耐腐蚀性能最好,Ecorr,icorr,CR分别为-0.318±0.013V,0.32±0.08μA/cm2及2.79±0.70μm/y r。4、SaOS_2成骨细胞试验表明,本文设计的三组Ti-Ta-Hf-Zr合金皆具有良好的生物相容性。本研究也进一步证实Hf的生物相容性与Ti,Zr和Ta接近。
[Abstract]:Because the titanium and its alloys have high specific strength, excellent corrosion resistance, biocompatibility and lower elastic modulus, is the research focus of biomedical materials. In addition to outside biological titanium alloy used in orthopedic surgery, dentistry, as the study of cardiovascular stent materials also gradually attention. At present, scaffold materials are commonly used two kinds of metal materials and polymer materials, high molecular materials, the performance of the metal stent is more stable, can provide better support strength of.316L SS stainless steel is one of the most commonly used material balloon expandable stents, Ni-Ti alloy is widely used as a self expandable stent material, however, they all contain Ni metal, it will cause the local immune response and inflammation. Therefore, we need a can meet the mechanical performance of the support required, and is a new material with good biocompatibility. The D alloy design based on average valence electron Concentration (e/a), molybdenum (Moeq) equivalent theory design method, designed and prepared a novel vascular stent with beta Ti-37Ta-26Hf-13Zr, Ti-40Ta-22Hf-11.7Zr and Ti-45Ta-18.4Hf-10Zr (wt.%) three groups of excellent performance and good biocompatibility of the alloy, and the use of optical microscopy, confocal microscopy, X ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness tester, electronic universal testing machine, electrochemical workstation, X ray photoelectron spectrometer system analyzes the microstructure of alloy, mechanical properties, corrosion resistance and biocompatibility, and the use of heat treatment, thermal mechanical forming methods optimize microstructure and properties. The main research work and conclusions are as follows: 1, three groups of Ti-Ta-Hf-Zr design of cast alloy with high strength (compressive strength, tensile strength and tensile yield strength), elastic allowable strain and microhardness. Basic with excellent mechanical properties The performance requirements of foot self expanding stent application should be allowed. In combination may provide greater potential for the design of more thin-wall support with high yield strength and high elasticity, to reduce the metallic stent restenosis rate, but the elongation of the alloy to be improved.2, solid solution and aging treatment, with the aging time of the extension of the microstructure of Ti-40Ta-22Hf-11.7Zr alloy change: beta + Omega ATH, beta, beta + alpha ", alpha + beta + alpha to beta + alpha + Omega ISO, the strength of the alloy, the hardness increased with the increase of aging time, the ductility decreases. The solid solution state when the alloy exhibits excellent compression performance, the compressive yield strength of about for 1018 MPa, the compressive strain is 70%, not the fracturing results show.OCP Ti-40Ta-22Hf-11.7Zr as cast corrosion resistance is better than that of cp-Ti and Ti6Al4V. had excellent corrosion resistance due to the formation of Ti O2, Hf O2, Ta2O5 alloy, Zr O2 and Zr2O3.3 film, low deformation during hot rolling (20%, 60%), Ti-40Ta-22Hf-11.7Zr alloy stress induced martensite organization, large deformation "alpha (80%, 90%) during hot rolling, dynamic recrystallization, grain refinement, the grain size of the solid solution state when the 335.3 m reduced to about 12.4 m. Due to the dislocation, fine grain strengthening and other factors. The mechanical properties of the alloy is cast, solid solution of a certain improvement. After solution treatment, the process of organizational experience, recrystallization and grain growth of the strength, hardness, Young's modulus decreased slightly, but the elongation, elastic allowable strain greatly improved. When the deformation is 90%. The optimal comprehensive performance, at this time, the micro hardness: 347.3 + 8 HV, tensile strength: 1272.4 + 37.6 MPa, yield strength: 1231.8 + 33.5 MPa, elongation: 9.69 + 0.26%, 62.9 + 2.1 Gpa.: Young's modulus especially elastic allowable strain reached 1.96 + 0.05%, comparable to the bulk metal elastic allowable strain is known Glass (BMG). At this time, the corrosion resistance of alloy Ecorr, icorr, CR, respectively, -0.318 + 0.013V, 0.32 + 0.08 and 2.79 + 0.70 m/y A/cm2 r.4, SaOS_2 osteoblast test showed that three groups of Ti-Ta-Hf-Zr alloy are designed in this paper has good biocompatibility. This study also further confirmed the compatibility with Ti Hf Zr and Ta biology, close.

【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R318.08;TG146.23

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