【摘要】：鋯合金具有良好的生物相容性、較好的綜合力學(xué)性能、耐腐蝕性好等特性,可作為生物醫(yī)學(xué)植入材料。然而,鋯合金尚難以滿足植入體在耐磨性、耐腐蝕性等方面的使用要求。氧化物陶瓷具有耐磨性好、耐蝕性強(qiáng)等優(yōu)點(diǎn),但易脆性斷裂使其難以單獨(dú)作為醫(yī)學(xué)植入體的優(yōu)先材料。有鑒于此,本論文結(jié)合金屬和氧化物陶瓷的性能優(yōu)勢,以鋯鈮合金為研究對象,利用高溫氧化方法在其表面原位形成陶瓷層,以獲得表面高耐磨、整體高強(qiáng)韌的醫(yī)學(xué)植入材料。同時(shí),本論文還利用劇塑性變形細(xì)化鋯鈮合金的晶粒,對比研究氧化參數(shù)對不同晶粒尺寸鋯鈮合金氧化動(dòng)力學(xué)、組織結(jié)構(gòu)、力學(xué)性能、耐蝕性能和生物相容性的影響規(guī)律,以期獲得綜合性能更為優(yōu)異的氧化陶瓷層。因此,本論文對醫(yī)用鋯鈮合金的組織性能設(shè)計(jì)和工程應(yīng)用,具有非常重要的科學(xué)和工程意義。首先,研究了Zr-2.1Nb合金在550~650℃保溫8h的氧化動(dòng)力學(xué)。開始階段氧化增重遵循拋物線規(guī)律,但在650℃約4h氧化增重轉(zhuǎn)變?yōu)榫�性規(guī)律,發(fā)生氧化轉(zhuǎn)折現(xiàn)象,此時(shí)氧化層中所含t-Zr O2向m-Zr O2轉(zhuǎn)變速度的增加以及明顯的裂紋缺陷引起氧化層保護(hù)作用的破壞。在550℃氧化6h、600℃氧化4h以及650℃氧化1h的優(yōu)選氧化工藝條件下,獲得了足夠厚、少或無缺陷的4-6μm厚氧化陶瓷層,其維氏硬度為987HV,為基體金屬硬度220HV的5倍;沿著氧化層截面方向,硬度逐漸下降直至基體的硬度,表明存在一個(gè)厚度約5?m的富氧擴(kuò)散層;另外,由于表面生成的氧化陶瓷硬化層,使氧化后的鋯鈮合金屈服強(qiáng)度提高了70MPa。隨后,研究了軋制形變量為60%鋯鈮合金的高溫氧化行為。結(jié)果表明,與未形變的鋯鈮合金相比,形變對鋯鈮合金在550~650℃的氧化動(dòng)力學(xué)機(jī)制并未產(chǎn)生明顯影響,但氧化增重更小。由于形變合金細(xì)化的晶粒和存在的內(nèi)應(yīng)力使得氧化層中t-Zr O2的體積分?jǐn)?shù)更高,有利于提高氧化層的致密性,故其氧化陶瓷層的表面硬度大幅提升,最高可達(dá)1217HV。此外,形變還大幅增加富氧擴(kuò)散層的厚度、減緩其硬度下降的趨勢,富氧擴(kuò)散層最厚可達(dá)35?m,遠(yuǎn)深于未變形合金所形成的近5?m的富氧擴(kuò)散層。經(jīng)過600℃氧化4h后形變鋯鈮合金的塑性從19.4%大幅增加至32.6%,而強(qiáng)度未明顯下降。對比研究了鋯鈮合金、氧化鋯鈮合金及形變氧化鋯鈮合金的耐磨性能。結(jié)果表明,氧化后鋯鈮合金的耐磨性能明顯優(yōu)于基體合金,其中表面氧化層硬度更高、更致密的形變氧化鋯鈮合金的耐磨性能最優(yōu)。特別是在較小的載荷力條件下(25N),氧化鋯鈮合金在磨損20min時(shí)其磨損量仍低于2mg,表現(xiàn)出更優(yōu)異的耐磨性。研究了鋯鈮合金、氧化鋯鈮合金及形變氧化鋯鈮合金的耐腐蝕性能。在林格模擬體液中,三種合金的穩(wěn)定性分別是形變氧化合金氧化合金基體合金。同時(shí),經(jīng)過氧化的合金的腐蝕速率較基體低2-3個(gè)數(shù)量級,其中氧化陶瓷層的致密性也明顯影響其耐腐蝕性,形變氧化合金腐蝕速率最低,表現(xiàn)出更為優(yōu)異的耐腐蝕性。另外,細(xì)胞毒性實(shí)驗(yàn)表明,三種鋯鈮合金對細(xì)胞的毒副作用影響均較小,毒性低于Ⅰ級,顯示出優(yōu)異的生物相容性。其中形變氧化合金的耐腐蝕性與生物相容性最優(yōu),更適合用作生物醫(yī)用材料。
[Abstract]:Zirconium alloys have good biocompatibility, good comprehensive mechanical properties, good corrosion resistance and so on, which can be used as biomedical implants. However, zirconium alloys are difficult to meet the requirements of wear resistance and corrosion resistance of the implants. Oxide ceramics have the advantages of good wear resistance and strong corrosion resistance, but brittle fracture makes it easy to fracture. It is difficult to be used as a priority material for medical implants. In view of this, this paper combines the performance advantages of metal and oxide ceramics, using the zirconium niobium alloy as the research object, using the high temperature oxidation method to form the ceramic layer on its surface in order to obtain the high wear resistance, high strength and toughness of the medical implant material. The grain of zirconium niobium alloy is refined by sexual deformation, and the influence of oxidation parameters on the oxidation kinetics, microstructure, mechanical properties, corrosion resistance and biocompatibility of zirconium niobium alloy with different grain sizes is studied in order to obtain a more excellent oxidation ceramic layer. Therefore, the structure and properties of the medical zirconium niobium alloy are designed and used in this paper. Engineering application is of very important scientific and engineering significance. First, the oxidation kinetics of Zr-2.1Nb alloy at 550~650 C for 8h is studied. At the beginning, the oxidation weight gain follows the parabolic law, but the oxidation weight of 4H is changed into a linear rule at 650 C, and the oxidation turning phenomenon occurs. At this time, the t-Zr O2 in the oxidation layer is transferred to m-Zr O2. Under the optimum oxidation process of oxidation of 6h at 550 degrees centigrade, 4H oxidation at 600, and oxidation of 1H at 650 C, a thick, less or no defect 4-6 mu m thick oxidation ceramic layer has been obtained at 550 degrees centigrade, and the hardness of the Vivtorinox is 987HV, which is 5 times of the matrix metal hardness 220HV, and along the oxidation layer. In the face direction, the hardness gradually descends until the hardness of the matrix, indicating the existence of an oxygen rich diffusion layer with a thickness of about 5? M. In addition, the yield strength of the zirconium niobium alloy after oxidation is increased by 70MPa., due to the oxidation ceramic hardening layer formed on the surface, and the high temperature oxidation behavior of the rolling variable is 60% zirconium niobium alloy. The results show that it is undeformed and undeformed. Compared with the Zr niobium alloy, the deformation has no obvious influence on the oxidation kinetics mechanism of Zr niobium alloy at 550~650 C, but the oxidation weight is smaller. Due to the grain refinement of the deformed alloy and the internal stress, the volume fraction of the t-Zr O2 in the oxide layer is higher, which is beneficial to the increase of the densification of the oxide layer, so the surface hardness of the oxidized ceramic layer is hard. In addition, the height can be up to 1217HV., and the deformation also greatly increases the thickness of the oxygen enriched layer and slows down the tendency of its hardness drop. The thickest oxygen diffusion layer is up to 35? M, which is far deeper than the oxygen rich diffusion layer of nearly 5? M formed by undeformed alloy. After 4H oxidation, the plasticity of the deformation zirconium niobium alloy increases from 19.4% to 32.6%, and the strength of the alloy is strong to 32.6%. The wear resistance of zirconium niobium alloy, zirconium niobium oxide alloy and deformed zirconium niobium alloy is compared and studied. The results show that the wear resistance of the zirconium niobium alloy after oxidation is obviously better than that of the matrix alloy, of which the surface oxidation layer is higher, and the more compact deformed zirconium niobium alloy has the best wear resistance, especially in the smaller load. Under the stress condition (25N), the wear resistance of Zr niobium alloy is still lower than that of 2mg at 20min. The corrosion resistance of zirconium niobium alloy, zirconium niobium alloy and deformed zirconium niobium alloy is studied. The stability of the three alloys in the simulated body fluid of Ringer's alloy is a deformed alloy oxide alloy matrix alloy. At the same time, the corrosion rate of the oxidized alloy is 2-3 orders of magnitude lower than that of the matrix, and the densification of the oxidized ceramic layer also obviously affects its corrosion resistance, the corrosion rate of the deformed alloy is the lowest and the corrosion resistance is more excellent. In addition, the cytotoxicity test shows that the toxic and side effects of the three kinds of zirconium niobium alloys are small, The toxicity is lower than grade I and shows excellent biocompatibility. The corrosion resistance and biocompatibility of the deformed alloy are best, and it is more suitable to be used as a biomedical material.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TG174.4

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