本文選題：鎂合金 + 生物降解性能��； 參考：《太原理工大學(xué)》2016年碩士論文

【摘要】：生物可降解鎂合金作為新一代的醫(yī)用工程材料受到人們?cè)絹?lái)越多的關(guān)注。與傳統(tǒng)的醫(yī)用金屬植入材料不銹鋼、鈦合金等相比,鎂合金鑄造性能良好,比剛度、比強(qiáng)度高,彈性模量(E=41-45 GPa)、密度(ρ=1.74-2.0g?cm-3)與人體骨骼接近(E=3-20GPa,ρ=1.8-2.1g?cm-3),在組織修復(fù)過(guò)程中不會(huì)造成應(yīng)力遮擋。研究表明鎂合金在人體內(nèi)具有良好的生物相容性,但作為植入材料,鎂合金在人體內(nèi)降解過(guò)快且腐蝕降解不均勻會(huì)導(dǎo)致其機(jī)械完整性提前喪失。同時(shí),鎂合金植入材料在快速降解過(guò)程中發(fā)生的副反應(yīng)會(huì)影響材料植入部位的pH平衡,并產(chǎn)生大量氫氣囊,影響骨骼生長(zhǎng),無(wú)法滿足植入后的骨支撐、骨誘導(dǎo)等服役性能要求。本文針對(duì)鎂合金作為生物醫(yī)用材料降解速率過(guò)快的弊端,采用重力鑄造法制備出摻雜有生物活性元素Zn和能大幅度提升合金基體電位的稀土元素Nd的Mg-4Zn-xNd(x=0,1,2,3 wt.%)鑄態(tài)鎂合金,先后通過(guò)電化學(xué)實(shí)驗(yàn)(極化曲線、阻抗譜)和浸漬試驗(yàn)(失重法)等方法研究了Nd含量和熱處理過(guò)程(固溶處理工藝、熱擠壓工藝和退火工藝)對(duì)Mg-4Zn-xNd鎂合金生物降解性能的影響,并對(duì)它的腐蝕機(jī)制進(jìn)行了探討。并進(jìn)一步通過(guò)體外生物相容性實(shí)驗(yàn),研究了Mg-4Zn-xNd合金的降解過(guò)程對(duì)其細(xì)胞相容性的影響。研究結(jié)果表明:(1)二元Mg-4Zn合金中的主要物相為α-Mg基體和少量的二元相Mg0.97Zn0.03,三元Mg-4Zn-xNd合金中的主要物相為α-Mg基體和二元相Mg12Nd。稀土元素Nd的添加導(dǎo)致大量Mg12Nd第二相沿晶界位置析出,并使合金的晶粒尺寸顯著細(xì)化,同時(shí)三元合金的腐蝕速率降低30%左右。鑄態(tài)合金先后在420oC、24h和510oC、4h條件下進(jìn)行固溶處理后,第二相含量明顯降低,晶粒尺寸增大,合金的腐蝕速率降低40%左右,其中Mg-4Zn-2Nd表現(xiàn)出最好的耐腐蝕性能。(2)固溶態(tài)Mg-4Zn-2Nd合金在擠壓比為16:1,擠壓速度為2mm/s,擠壓溫度分別為350oC,370oC,390oC,410oC條件下進(jìn)行熱擠壓處理后,晶粒尺寸減小,且隨著溫度升高,擠壓態(tài)合金的晶粒尺寸增大、第二相含量降低,合金的耐腐蝕性能得到不同程度的提高,當(dāng)擠壓溫度為370oC時(shí),腐蝕速率最低,達(dá)到3.4mm/y。(3)370oC擠壓態(tài)合金在退火溫度為420oC,退火時(shí)間分別為5min,15min,30min,60min,120min的退火工藝條件下進(jìn)行退火處理,隨著退火時(shí)間延長(zhǎng),合金的晶粒尺寸持續(xù)增大,第二相持續(xù)析出,加工殘余應(yīng)力逐漸減小,導(dǎo)致合金的腐蝕速率逐漸增大。(4)對(duì)比鑄態(tài)、固溶態(tài)、擠壓態(tài)和退火態(tài)合金的腐蝕速率與細(xì)胞實(shí)驗(yàn)結(jié)果表明,鎂合金的腐蝕速率對(duì)MC3T3-E1成骨細(xì)胞在其表面的粘附、活性及分化影響較大;適量的Nd摻雜在提高合金耐腐蝕性能的同時(shí)促進(jìn)細(xì)胞的粘附、鋪展;熱處理工藝導(dǎo)致合金第二相含量及晶粒尺寸發(fā)生變化,影響合金的耐腐蝕性能,腐蝕速率的加快抑制了細(xì)胞的粘附、增殖及分化過(guò)程。
[Abstract]:As a new generation of medical engineering materials, biodegradable magnesium alloys have attracted more and more attention. Compared with traditional medical metal implant materials, such as stainless steel and titanium alloy, magnesium alloy has good casting properties, high specific stiffness, high specific strength, elastic modulus of 41-45 GPaan, density (蟻 _ (1.74-2.0) g / cm ~ (-3) close to that of human skeleton (E _ (3-20), 蟻 _ (1.8-2.1) g / cm ~ (-3), and does not cause stress shielding in the process of tissue repair. The results show that magnesium alloy has good biocompatibility in human body, but as implant material, magnesium alloy degrades too quickly and corrosion degradation inhomogeneously in human body will lead to early loss of mechanical integrity of magnesium alloy. At the same time, the side effects of magnesium alloy implant during rapid degradation will affect the pH balance of the implanted site and produce a large number of hydrogen balloon, which can not meet the requirements of service performance such as bone support and bone induction. In this paper, aiming at the disadvantage of rapid degradation rate of magnesium alloy as biomedical material, magnesium alloy Mg-4Zn-xNdndndndndndndndndndnndndcndndndndndndndndndndnd0OO012wt.g doped with biological active element Zn and rare earth element ND with biological active element Zn and ND were prepared by gravity casting method. The ND content and heat treatment process (solid solution treatment) were studied by electrochemical experiment (polarization curve, impedance spectroscopy) and impregnation test (weightlessness method). The effect of hot extrusion and annealing on the biodegradability of Mg-4Zn-xNd magnesium alloy and its corrosion mechanism were discussed. The effect of degradation process on the biocompatibility of Mg-4Zn-xNd alloy was studied by biocompatibility experiment in vitro. The results show that the main phases in binary Mg-4Zn alloy are 偽 -Mg matrix and a small amount of binary phase Mg0.97Zn0.03, and the main phases in ternary Mg-4Zn-xNd alloy are 偽 -Mg matrix and binary phase Mg12Nd. The addition of rare earth element ND resulted in the precipitation of a large number of Mg12Nd second phases along the grain boundary, and the grain size of the alloy was significantly refined, and the corrosion rate of the ternary alloy was reduced by about 30%. After solution treatment at 420oC ~ (2 +) for 24 h and 510oC _ (4) for 4 h, the content of the second phase decreased obviously, the grain size increased, and the corrosion rate of the alloy decreased by about 40%. Mg-4Zn-2Nd shows the best corrosion resistance.) the grain size of Mg-4Zn-2Nd alloy decreases with increasing temperature after hot extrusion treatment under the condition of extrusion ratio of 16: 1, extrusion speed of 2mm / s and extrusion temperature of 350oC ~ 370oC ~ 390oC ~ (410oC). When the grain size of extruded alloy increases and the second phase content decreases, the corrosion resistance of the alloy is improved to some extent. When the extrusion temperature is 370oC, the corrosion rate is the lowest. When the annealing temperature is 420 OC and the annealing time is 5 min ~ 15 min ~ 30 min ~ 60 min ~ 120 min respectively, the 3.4mm/y.(3)370oC extruded alloy is annealed. With the increase of annealing time, the grain size of the alloy increases and the second phase continues to precipitate. The results of cell experiments show that the corrosion rate of as-cast, solid solution, extruded and annealed alloys is higher than that of as-cast, extruded and annealed alloys. The corrosion rate of magnesium alloy has a great effect on the adhesion, activity and differentiation of MC3T3-E1 osteoblasts on its surface. The second phase content and grain size of the alloy were changed by heat treatment, which affected the corrosion resistance of the alloy, and the accelerated corrosion rate inhibited the cell adhesion, proliferation and differentiation.
【學(xué)位授予單位】：太原理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：TG146.22;TG166.4;TG379

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1 鄧偉林;基于Mg-4Zn-xNd鎂合金植入體的制備及其生物可降解性能的研究[D];太原理工大學(xué);2016年

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本文編號(hào)：1894548