新型生物医用Mg-Dy-Sr-Nd-Zr合金及其压铸态的组织与性能研究
[Abstract]:With its good biocompatibility, mechanical compatibility and biodegradability, the biological magnesium alloy material is widely concerned by the medical community and the material world, but the control and precision molding of the degradation process have limited its clinical application in the medical field. In recent years, rare earth elements have become hot spots in the alloying of magnesium alloy materials, and the WE43 medical magnesium alloy containing rare earth has good mechanical properties and corrosion resistance. In order to develop a biological medical magnesium alloy which is more suitable for human environment, the rare earth element is replaced on the basis of the WE43 alloy, and the rare earth element Dy with no toxicity and the element Sr with good biocompatibility are selected as the alloying elements. Mg-xDy-ySr-2.4 Nd-0.5Zr (x = 2,6,10; y = 0.5, 1.5,2) alloy was prepared by metal mold casting, and the microstructure of the biological medical magnesium alloy material was analyzed by optical microscope (O M), scanning electron microscope (SEM), room temperature tensile test, electrochemical and weight loss experiment. And the effect of the mechanical property and the biodegradability. In order to solve the problem of the plastic difference of the biological magnesium alloy, an Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy with good mechanical properties and corrosion resistance is adopted to adopt a die-casting forming process, and the internal law of the microstructure and the property of the as-cast and die-cast biomedical magnesium alloy is compared and analyzed. The grain size of the as-cast Mg-xDy-ySr-2.4 Nd-0.5Zr alloy is dendritic growth, and the average grain size of the as-cast Mg-xDy-ySr-2.4 Nd-0.5Zr alloy is obviously refined with the increase of the content of the Dy element. The effect of Sr element on the grain size refinement of the biological magnesium alloy is not obvious, but the excessive Sr element will increase the tendency of the magnesium alloy to become more and more. The second phase in the as-cast alloy is composed of Mg2 Dy, Mg3Dy, Mg17Sr2 and Mg12Nd and is precipitated along the grain boundary. The increase of the D y element can improve the mechanical properties of the magnesium alloy by solution strengthening and fine grain strengthening. However, the excessive Sr element results in uneven distribution of the grain distribution of the magnesium alloy, and the stress concentration is generated, so the mechanical property of the magnesium alloy decreases with the increase of the Sr content. As-cast biomedical Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy has the best mechanical property, and its tensile strength, yield strength and elongation are 203 MPa,128 MPa and 7.4%. The corrosion resistance of the biomedical Mg-xDy-ySr-2.4 Nd-0.5Zr alloy can be enhanced by refining the crystal grains with the increase of the Dy element. Mg17Sr2 is susceptible to galvanic corrosion with the Mg-Mg phase, so the corrosion rate of the magnesium alloy increases with the increase of Sr element content. As-cast Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy has the best corrosion resistance in the body fluid of PBS, and the degradation rate is 0.58mm/ a. The phase composition of the Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy is not changed in the die-casting process, but the second phase along the grain boundary is distributed in a fine mesh shape. The grain size of the die-cast alloy is obviously thinned to 18 & mu; m, and the grain morphology is changed from the dendritic to the like. The grain size is not uniform and the air holes in the alloy lead to the decrease of the strength of the die-cast Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy, but the tensile fracture of the die-cast magnesium alloy has a large number of dimple and tear edges, and the elongation is increased, indicating that the plasticity of the die-cast Mg-10Dy-0.5Sr-2.4Nd-0.5Zr alloy is obviously enhanced, The fracture type belongs to the quasi-cleavage fracture. Therefore, the die-casting technology improves the plastic deformation capacity of the biomedical magnesium alloy. The dissolution rate of the corrosion product of the magnesium alloy in the die-casting state is higher than the repair rate, and the stable Mg (OH)2 protective film is not formed in the corrosion layer of the magnesium alloy, and the polarization curve also shows that the magnesium alloy in the die-casting state has no passivation behavior. And the corrosion resistance of the Mg-10Dy-0.5Sr-2.4 Nd-0.5Zr alloy is reduced. The corrosion type of the magnesium alloy in the die-casting state has also changed, and the local point corrosion of the as-cast alloy is changed into uniform corrosion.
【学位授予单位】:兰州理工大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:R318.08;TG146.22;TG249.2
【参考文献】
相关期刊论文 前10条
1 马莹;郭阳;张忠明;徐春杰;吕振林;;Ca对铸态Mg-4Zn合金组织及腐蚀性能的影响[J];材料热处理学报;2015年01期
2 郁元正;;保温温度对AM60B镁合金压铸组织和性能的影响[J];铸造技术;2015年01期
3 王峰;张峰;刘静;毛萍莉;刘正;;真空压铸对AZ91镁合金组织及性能的影响[J];铸造;2015年01期
4 王栀沁;张彬;李德江;Robert FRITZSCH;曾小勤;Hans J.ROVEN;丁文江;;热处理工艺对高真空压铸Mg 8Gd 3Y 0.4Zr镁合金组织及力学性能的影响(英文)[J];Transactions of Nonferrous Metals Society of China;2014年12期
5 李胜勇;李德江;曾小勤;丁文江;;真空压铸Mg-6Gd-3Y-0.5Zr镁合金的组织与性能(英文)[J];Transactions of Nonferrous Metals Society of China;2014年12期
6 李胜勇;李德江;曾小勤;丁文江;;压铸Mg-3Nd-0.2Zn-0.4Zr合金的组织和力学性能研究[J];铸造;2014年12期
7 彭勃;章晓波;王章忠;;Sr含量对Mg-Nd-Zr合金显微组织与力学性能的影响[J];金属热处理;2014年11期
8 Jing Bai;Lingling Yin;Ye Lu;Yiwei Gan;Feng Xue;Chenglin Chu;Jingli Yan;Kai Yan;Xiaofeng Wan;Zhejun Tang;;Preparation, microstructure and degradation performance of biomedical magnesium alloy fine wires[J];Progress in Natural Science:Materials International;2014年05期
9 于照鹏;王柏树;熊守美;;压铸工艺对AT72镁合金力学性能的影响[J];特种铸造及有色合金;2014年04期
10 张兴凯;韩伟;郑玉峰;范德增;;纯镁材表面化学镀铁[J];材料保护;2014年04期
相关硕士学位论文 前1条
1 蔡淑华;Mg-Zn-Sr系医用镁合金材料的制备及其性能的研究[D];中南大学;2013年
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