Mn、Sr、Sn对Mg-Zn-Ca合金非晶形成能力、腐蚀和压缩性能的影响

发布时间：2018-04-01 05:26

本文选题：Mg-Zn-Ca非晶合金　切入点：非晶复合材料　出处：《西安工业大学》2017年硕士论文

【摘要】：相较于其他生物植入材料,镁及其合金在密度、强度、弹性模量等方面存在着无可比拟的优势。近年来,将其作为可降解金属植入材料引起了人们的广泛关注。然而,镁及镁合金的生物应用由于腐蚀降解过快而受到限制。已有研究结果表明,Mg-Zn-Ca系列非晶合金具有良好的生物相容性、优异的力学性能和耐蚀性,作为可降解生物医用材料具有潜在的临床应用价值。目前,Mg-Zn-Ca系合金非晶形成能力和腐蚀降解行为方面的研究还较少。本文以Mg_(65)Zn_(30)Ca_5合金为研究对象,采用熔体旋淬法和铜模喷铸法制备了薄带状和棒状试样,通过XRD、SEM、DSC、电化学测试和压缩实验来研究了合金化元素Mn、Sr、Sn对Mg-Zn-Ca合金非晶形成能力、腐蚀和压缩性能的影响规律,取得以下结果:(1)Mn元素的影响。利用熔融纺丝法和喷铸法制备的Mg_(65)Zn_(30)Ca_5带材和2mm棒材试样均为完全非晶结构;添加不同含量的Mn元素时,带材试样依然为非晶结构,而2mm棒材试样组织中逐渐析出了Mg相、Mn相、MgZn相,表明添加Mn元素损害了Mg_(65)Zn_(30)Ca_5的非晶形成能力。2mm棒材试样电化学测试和浸泡实验结果表明,处于完全非晶态的Mg_(65)Zn_(30)Ca_5合金耐蚀性最好,Mn元素添加量小于0.2at%时合金的耐蚀性影响不大。而当掺杂Mn元素含量大于0.2at%时,合金的耐蚀性随Mn添加量增加明显下降。压缩力学实验结果表明Mg_(65)Zn_(30)Ca_5的强度最高,为531.8MPa,加入Mn元素后使得合金的强度逐渐下降。(2)Sr元素的影响。在Mg_(65)Zn_(30)Ca_5合金中加入Sr元素,合金的非晶形成能力先随Sr加入量的增加不断提高,当Sr添加量为1at%时,合金具有最大的非晶形成能力。继续增加Sr元素的添加量,合金的非晶形成能力反而减弱。2mm和4mm棒材试样的电化学和浸泡实验结果表明,含Sr试样的耐蚀性均优于不含Sr的Mg_(65)Zn_(30)Ca_5试样,即加入Sr元素提高了合金的耐蚀性。力学实验测试表明掺杂0.5at%、1.0at%、1.5at%的Sr元素后,合金的压缩强度分别提高了4.07%、7.06%、1.57%,但塑性基本不变。(3)Sn元素的影响。不同Sn含量的薄带试样均为完全非晶态,而2mm棒材试样的组织结构由不含Sn的完全非晶态逐渐转变为由Mg相和Mg2Sn相组成的晶态,且析出晶体相的体积分数和尺寸随着Sn含量的增加而增大,说明掺杂Sn元素降低了Mg-Zn-Ca合金的非晶形成能力。电化学测试和力学性能测试结果表明,随着Sn元素加入量的增加,合金的耐蚀性和压缩性能逐渐下降。
[Abstract]:Compared with other biological implants, magnesium and its alloys have unparalleled advantages in density, strength, elastic modulus and so on. In recent years, magnesium and its alloys have attracted much attention as biodegradable metal implants. The bioapplications of magnesium and magnesium alloys are limited by the rapid corrosion degradation. The results show that the Mg-Zn-Ca series amorphous alloys have good biocompatibility, excellent mechanical properties and corrosion resistance. As a biodegradable biomedical material, it has potential clinical application value. At present, there are few studies on amorphous forming ability and corrosion degradation behavior of Mg-Zn-Ca alloy. In this paper, Mg_(65)Zn_(30)Ca_5 alloy is taken as the research object. The thin strip and rod specimens were prepared by melt spinning and copper die spray casting. The effects of alloying element Mn-Sr-Sn on the amorphous forming ability, corrosion and compression properties of Mg-Zn-Ca alloy were studied by means of electrochemical test and compression test. The following results were obtained: the samples of Mg_(65)Zn_(30)Ca_5 strip and 2mm bar prepared by melt spinning method and spray casting method were all completely amorphous, and when different contents of mn element were added, the sample of Mg_(65)Zn_(30)Ca_5 strip was still amorphous structure. However, mg phase, mn phase and mg Zn phase were gradually precipitated in the microstructure of 2mm bar, which indicated that the addition of mn element damaged the amorphous forming ability of Mg_(65)Zn_(30)Ca_5. The corrosion resistance of Mg_(65)Zn_(30)Ca_5 alloy in completely amorphous state is the best when the content of mn element is less than 0.2 at%. The corrosion resistance of Mg_(65)Zn_(30)Ca_5 alloy with doping mn content greater than 0.2 at% has little effect on the corrosion resistance of the alloy. The corrosion resistance of the alloy decreased obviously with the increase of mn content. The compressive mechanical test results showed that the strength of Mg_(65)Zn_(30)Ca_5 was the highest (531.8 MPA). The strength of the alloy decreased gradually after adding mn element. The effect of Sr element on the strength of the alloy was observed. Sr element was added to the Mg_(65)Zn_(30)Ca_5 alloy. The amorphous forming ability of the alloy first increases with the increase of Sr content. When the Sr content is 1 at%, the alloy has the largest amorphous forming ability. On the contrary, the amorphous forming ability of the alloy was weakened. The electrochemical and immersion tests of the specimens of 0.2mm and 4mm bars showed that the corrosion resistance of the samples containing Sr was better than that of the samples without Sr, and the corrosion resistance of the specimens containing Sr was better than that of the samples without Sr. That is, the corrosion resistance of the alloy was improved by adding Sr element. The compressive strength of the alloy was increased by 4.07 and 7.06, respectively, but the plasticity of the alloy was almost unchanged. The thin strip samples with different Sn contents were completely amorphous. However, the microstructure of 2mm bars was gradually changed from a completely amorphous state without Sn to a crystalline state composed of mg phase and Mg2Sn phase, and the volume fraction and size of precipitated crystal phase increased with the increase of Sn content. The results of electrochemical and mechanical properties tests show that the corrosion resistance and compressibility of Mg-Zn-Ca alloy decrease with the increase of Sn content.
【学位授予单位】：西安工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG139.8

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