Nd,Zn微量元素在Mg-Zn-Y-Nd血管合金支架中组织学特性和改性的变化

发布时间：2018-07-22 19:27

【摘要】：背景:随着材料学的不断发展,镁合金血管支架材料在心血管疾病中广泛运用,但是传统合金材料难以满足血管支架要求,因此采取有效措施完成支架表面改性,提高血管支架的组织、力学性能具有深远的意义。目的:观察血管支架在快速凝固Mg-Zn-Y-Nd合金中的组织学及表面改性情况。方法:选择具备良好力学性能、耐腐蚀性能的低锌系Mg-2Zn-0.2Y合金为基本材料,向材料中加入Nd,Zn元素完成合金支架的细化;经过对支架的挤压细化组织性能完成支架表面改性,提高合金材料的综合性能,获得血管支架用新型镁合金并完成支架表面改性。通过金相显微组织、扫描电镜能谱及射线衍射分析实验了解制备支架的组织性能;通过硬度、拉伸实验了解支架的力学性能。结果与结论:(1)金相显微镜组织观察结果显示:当不加入Y时,镁合金支架第2相为杆状,存在少许颗粒嵌入在基体中;当向镁合金支架中混入0.5%Y元素时,支架第2相中杆状物明显减少,以颗粒状为主,且均匀分布在机体中;加入1.0%的Y时,第2相数增加,晶粒中可见大量枝晶,第2相存在不连续杆状物;加入1.5%的Y时,合金组织中的大枝晶与局枝晶混合,第2相为杆状。(2)射线衍射分析实验结果表面:Mn-Zn-0.5Nd合金与Mn-Zn-1.0Nd合金中均含有相同的相(Mg4Zn7和(Nd,Y)2Zn17相)。当Nd浓度提高为1%时,合金中出现新的MgZ n2相;(3)镁合金改性材料SEM及EDS实验结果显示:镁合金改性后第2相中含有Zn元素、Nd及Y元素,并且Nd元素、Y元素含量和与Zn含量较接近。EDS分析可知:加入Zr元素后层片状第2相中Zn元素水平明显下降,Y元素、Nd元素含量提高,能获得更加稳定的性能;(4)显微硬度实验结果显示:随着镁合金含量的不断增加,合金显微硬度值不断增加;(5)拉伸实验结果显示:Mg-Zn-Y-0.5Nd-Zr支架的抗拉强度、屈服强度,显著高于Mg-Zn-Y-0.5Nd,Mg-Zn-Y-1.0Nd,Mg-Zn-Y-1.0Nd-Zr(P0.05);Mg-Zn-Y-0.5Nd-Zr,Mg-Zn-Y-1.0Nd-Zr伸长率,高于Mg-Zn-Y-0.5Nd,Mg-Zn-Y-1.0Nd(P0.05)。(6)结果说明:选择低锌系Mg-2Zn-0.2Y合金为核心材料,向材料中分别加入Nd,Zn等微量元素,完成材料的改性,并且经过对支架的挤压细化组织性能完成支架表面改性,改性后材料具有优良的性能。
[Abstract]:Background: with the development of material science, magnesium alloy vascular stent materials are widely used in cardiovascular diseases, but traditional alloy materials can not meet the requirements of vascular stent. Therefore, effective measures are taken to complete the surface modification of the stent. It is of great significance to improve the tissue and mechanical properties of vascular stent. Aim: to observe the histological and surface modification of vascular stent in rapidly solidified Mg-Zn-Y-ND alloy. Methods: low zinc system Mg-2Zn-0.2Y alloy with good mechanical properties and corrosion resistance was selected as the basic material, and the alloy bracket was refined by adding Ndzn Zn element to the material, and the surface modification of the scaffold could be completed by extrusion refinement of the scaffold. To improve the comprehensive properties of the alloy, a new type of magnesium alloy for vascular stent was obtained and the surface modification of the stent was completed. The microstructure and properties of the scaffold were studied by metallographic microstructure, SEM and XRD, and the mechanical properties of the scaffold were studied by hardness and tensile test. Results and conclusions: (1) the microstructure of magnesium alloy scaffolds showed that the second phase of magnesium alloy scaffolds was rod-like and a few particles were embedded in the matrix when Y was not added, and 0.5% Y element was added to the scaffolds. In the second phase of the scaffold, the number of the second phase was increased, and a large number of dendrites were observed in the second phase, and the second phase had discontinuous bar, and when 1.5% Y was added, there was a large number of dendrites in the second phase. The second phase is rod-like. (2) the results of X-ray diffraction analysis show that there are the same phases (Mg4Zn7 and (NdY) 2Zn17) in the surface of Mn-Zn-0.5Nd alloy and Mn-Zn-1.0ND alloy. When the concentration of ND is increased to 1, a new MgZ N2 phase appears in the alloy. (3) the SEM and EDS results of the modified magnesium alloy show that Zn elements ND and Y are present in the second phase of the modified magnesium alloy. The results of EDS analysis show that the content of Zn in the second phase of lamellar layer decreases obviously after the addition of Zr element, and the content of ND in Y element increases obviously after addition of Zr element, and the content of Y element in ND element is close to that of Zn element, which is similar to that of Zn element. (4) the results of microhardness test showed that the microhardness value of the alloy increased with the increasing of magnesium alloy content, (5) the tensile test results showed that the tensile strength and yield strength of the W Mg-Zn-Y-0.5Nd-Zr scaffold were increased. The results showed that Mg-Zn-Y-1.0Nd-Zr (P0.05) and Mg-Zn-Y-0.5Nd-ZrMg-Zn-Y-1.0Nd-Zr (P05) were higher than Mg-Zn-Y-0.5NdCU Mg-Zn-Y-1.0ND (P0.05). (6). The results showed that Mg-Zn-Y-1.0Nd-Zr (Mg-Zn-1.0Nd-Zr) alloy with low zinc content as the core material was modified by adding trace elements such as Ndzn Zn into the material. The surface of the scaffold can be modified by extruding and refining the microstructure of the scaffold, and the modified material has excellent properties.
【作者单位】：河南大学淮河医院;
【基金】：河南省科技攻关项目(2013HN01106)~~
【分类号】：R318.08;R54

【相似文献】