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  本文關(guān)鍵詞：生物可降解Ca-P陶瓷顆粒增強鎂基復合材料研究　出處：《天津理工大學》2015年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 鎂基復合材料 晶粒細化 熱模擬 等通道轉(zhuǎn)角擠壓 顯微組織 耐蝕性

【摘要】：重量輕、力學性能適宜、生物安全性高并可降解的鎂及鎂合金材料在骨修復器材、血管支架和止血夾等可降解植入材料方面孕育著巨大的臨床應用前景,但鎂及鎂合金在含有Cl-的生理環(huán)境中存在著降解速率過快的問題,因此可能帶來力學強度下降過快,p H值的升高以及氫氣產(chǎn)生等問題,這些問題是目前該類材料走向臨床應用的主要障礙。針對這一關(guān)鍵問題,本文采用復合化的形式,通過在鎂合金基體中添加Ca-P陶瓷顆粒,從而起到細化鎂合金基體晶粒以及提高基體的力學性能和耐蝕性能的作用。本文首先通過控制冷卻速率制備了不同晶粒大小的純鎂,采用真空熔煉制備了Mg-30%Ca合金,分別研究了晶粒尺寸和第二相對鎂合金腐蝕降解行為的影響。采用高剪切攪拌工藝制備1HA/Mg-3Zn-0.2Ca及1β-TCP/Mg-3Zn-0.2Ca復合材料,采用光學顯微鏡(OM)、掃描電子顯微鏡(SEM)、透射電鏡(TEM)、X射線衍射分析(XRD)從不同尺度觀察表征顯微組織;采用電化學測試的方法對合金及復合材料的腐蝕行為進行研究,采用熱模擬實驗研究增強相的添加對Mg-Zn-Zr合金熱變形行為的影響,將高剪切熔煉所制備的鑄態(tài)試樣采用等通道轉(zhuǎn)角擠壓(ECAE)進行變形處理,研究等通道轉(zhuǎn)角擠壓對復合材料的顯微組織、織構(gòu)及電化學行為的影響。主要結(jié)論為:1.隨著晶粒尺寸的減少,晶粒細化可以使鎂的腐蝕敏感性增加,但阻抗及浸泡實驗表明,細晶鎂在浸泡的過程中可以產(chǎn)生更致密的鈍化層,因此鎂基材料具有更好的耐腐蝕性。2.對于Mg-Ca合金來說,研究表明Mg2Ca相在基體中會作為陽極被優(yōu)先腐蝕與一般鎂合金中的第二相的作用有所不同。Mg-30wt%合金的長時間浸泡實驗(90d)表明,在合金浸泡腐蝕降解的后期會產(chǎn)生一些難降解的腐蝕產(chǎn)物,這些腐蝕產(chǎn)物是具有包覆結(jié)構(gòu)的微粒。3.HA和β-TCP的添加可以有效的細化Mg合金的晶粒,由于β-TCP與Mg基體具有更小的錯配度,所以其細化作用更加明顯。HA和β-TCP的添加還可以使鎂合金在浸泡過程中的鈍化層更具有保護性從而提高Mg基材料的耐腐蝕性。4.Mg-3Zn-0.8Zr合金以及HA/Mg-3Zn-0.8Zr復合材料的熱模擬實驗表明:在小于573K時,Mg-3Zn-0.8Zr合金的變形機制主要為位錯攀移控制的蠕變機制,大于623K時則部分轉(zhuǎn)變?yōu)榫Ы缁瑒拥淖冃螜C制,HA的添加則可以部分抑制晶界滑動變形機制的產(chǎn)生。并且HA的添加可以提高Mg-3Zn-0.8Zr合金在高溫下的峰值應力,這種情況的發(fā)生可能是由于晶粒尺寸減小或者晶內(nèi)分布的HA阻礙位錯運動造成。5.等通道轉(zhuǎn)角擠壓可以使鑄態(tài)1HA/Mg-Zn-Ca復合材料的晶粒得到細化,而且HA顆粒的團簇尺寸也隨著變形道次的增加而減少,復合材料的顯微組織更加均勻,ECAE的擠壓過程可以使試樣的ED面部分上與Mg晶格的基面平行,由于鎂晶格的基面具有更高的結(jié)合能,因此1HA/Mg-Zn-Ca復合材料的ED面具有更好的耐腐蝕性。
[Abstract]:Light weight, suitable mechanical properties, magnesium and magnesium alloy material with high biological safety and degradable in bone repair equipment, stent and clip etc. biodegradable implant materials has enormous clinical application prospects, but magnesium and magnesium alloy in physiological environment containing Cl- exists the problem of excessive degradation rate therefore, the mechanical strength may bring down too quickly, the p value of H and increase the hydrogen production, these problems are the main obstacle of this kind of materials to clinical application. To solve this problem, this paper adopts the composite form, through adding ceramic particles in Ca-P magnesium alloy matrix, so as to refine magnesium alloy matrix grain and improve the mechanical properties and corrosion resistance of the matrix. The effect of the pure magnesium with different grain size control the cooling rate of preparation of Mg-30% Ca alloy was prepared by vacuum melting method, The effects of grain size and the relative second magnesium alloy corrosion behavior were studied. The high shear mixing process and the preparation of 1HA/Mg-3Zn-0.2Ca 1 beta -TCP/Mg-3Zn-0.2Ca composite materials by using optical microscope (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X ray diffraction analysis (XRD) to observe the microstructure characterization from different scale; research on Corrosion Behavior of alloy by electrochemical method and composite materials, the thermal simulation experiment of reinforcement effect on deformation behavior of Mg-Zn-Zr alloy, high shear melting prepared by as cast samples by equal channel angular pressing (ECAE) deformation processing, microstructure of composite materials the study of ECAP, the effect of texture and electrochemical behavior. The main conclusions are as follows: 1. with the decrease of grain size, grain refinement can make the corrosion sensitivity of magnesium increased, But the impedance and immersion test showed that the passivation layer of fine grained magnesium can produce more dense in the soaking process, so magnesium based materials have better corrosion resistance for.2. Mg-Ca alloy, research shows that long time immersion test Mg2Ca as anode was the second priority and general corrosion in magnesium alloy phase in the matrix the effect of different.Mg-30wt% alloys (90d) show that in the late immersion corrosion degradation will produce some refractory corrosion products, the corrosion product is added with grain coating structure of the particle.3.HA and beta -TCP can refine Mg alloy effectively, because the beta -TCP and Mg matrix has a smaller mismatch so, adding the refinement effect is more obvious.HA and beta -TCP can also make the magnesium alloy passivation layer during the immersion is more protection in order to improve the corrosion resistance of.4.Mg-3Zn-0.8Zr Mg Composites Show that the thermal simulation experiment of gold and HA/Mg-3Zn-0.8Zr composite materials: in less than 573K, the deformation mechanism of Mg-3Zn-0.8Zr alloy is dislocation climb creep mechanism controlling the displacement of more than 623K, is partly transformed into the deformation mechanism of grain boundary sliding, the addition of HA can partially inhibit the grain boundary sliding deformation mechanism. The peak and the addition of HA improve Mg-3Zn-0.8Zr alloy under high temperature stress, this may happen due to the reduction of grain size or grain distribution of HA by hindering the movement of dislocation can make grain cast 1HA/ Mg-Zn-Ca composite materials were refined.5. and ECAP, the cluster size of HA particles with deformation times decrease and the microstructure of the composites is more uniform and the extrusion process of ECAE can make the basal part of the sample on the ED surface and the Mg lattice parallel to the magnesium base lattice The mask has a higher binding energy, so the 1HA/Mg-Zn-Ca composite's ED mask has better corrosion resistance.

【學位授予單位】：天津理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB333

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本文編號：1375019