杂质对超多元Zr基块体非晶合金形成及性能的影响

发布时间：2018-03-15 04:16

本文选题：超多元Zr基块体非晶合金　切入点：杂质　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：Zr基块体非晶合金拥有较传统晶态合金材料更高的弹性、强度、硬度、耐蚀性等优良的性能,是一种极具潜力的结构材料。但Zr基块体非晶合金的生产对杂质极其敏感,必须使用高纯原料和苛刻的生产条件才能制备,因而导致Zr基块体非晶合金的广泛应用受到了极大的限制。最近的研究显示,超多元Zr基块体非晶合金可以有效地降低杂质对其形成能力和性能的影响,具有很高的应用潜力,但杂质对其形成能力及性能的影响机制尚不清楚。本文以超多元Zr50Cu25Al10Ni7Ti4Co2Fe1Y1块体非晶合金为研究对象,通过添加不同质量分数的低纯Zr原料(海绵Zr),详细地研究了杂质对超多元Zr基块体非晶合金形成能力、热稳定性、力学性能和耐蚀性的影响。首先,本文研究了杂质对超多元Zr基块体非晶合金形成能力的影响。以过冷液相区宽度△Tx为判据,通过对不同杂质含量的超多元Zr基块体非晶合金试样进行DSC分析,发现它们的△Tx非常接近,杂质含量对超多元Zr基块体非晶合金的形成能力影响不大。其电弧熔炼后的直径为20 mm的铸锭在剪开后也呈现典型的玻璃状断口,且XRD结果显示其晶化程度较低,表现出其良好的非晶形成能力。其次,本文对不同含量海绵Zr制备的超多元Zr基块体非晶合金的热稳定性及晶化行为进行了进一步的系统研究。通过DSC曲线分析发现杂质对该合金的热稳定性影响不大,但会影响超多元Zr基块体非晶合金的晶化行为,并且随杂质含量的升高,其晶化过程更加复杂,晶化时间更长。对不同杂质含量的块体非晶合金的完全晶化产物进行分析发现,杂质含量不会影响该非晶合金的晶化产物,析出相主要具有CuZr2、Cu10Zr7和多种ZrAl相结构。最后,本文又分析了不同含量海绵Zr制备的超多元Zr基块体非晶合金的力学和化学性能。通过室温准静态压缩试验可知,含杂质的超多元Zr基块体非晶合金的强度、硬度都很高,变化不大,但杂质含量的不同对该合金的塑性有着不同的影响,低浓度杂质含量不会使合金基体脆化,对塑性影响不大,而当海绵Zr的质量分数达到80%以上时,塑性可达6.7%,是高纯原料制备时的3倍。杂质诱发基体原位析出5 nm左右的纳米相,导致块体非晶合金的塑性极大地提升。此外,高纯原料制备的超多元Zr基块体非晶合金在经过低温弛豫后塑性大幅升高,而高杂质含量的超多元Zr基块体非晶合金在经过低温弛豫后塑性有所下降。这可能是因为高纯原料制备的超多元Zr基块体非晶合金在低温弛豫时导致了成分不均匀性的提升,而高杂质含量的超多元Zr基块体非晶合金中纳米晶的作用会随着自由体积的减少而减弱。电化学腐蚀实验显示杂质的存在不会显著地影响超多元Zr基块体非晶合金的自腐蚀电位,意味着杂质对超多元Zr基块体非晶合金的耐蚀性没有明显影响。
[Abstract]:Zr based bulk amorphous alloy has a traditional amorphous alloy materials of high elasticity, strength, hardness, corrosion resistance and other excellent properties, is a kind of potential structural material. But the Zr based bulk amorphous alloy production is extremely sensitive to impurities, must use high pure raw materials and strict production conditions the preparation, which lead to the extensive application of Zr based bulk amorphous alloy has been greatly restricted. Recent studies have shown that the super multi Zr based bulk amorphous alloys can effectively reduce the influence of impurity forming ability and on its performance, has very high application potential, but the mechanism of the effect of impurity forming ability and performance for it is not clear. In this paper, super multi Zr50Cu25Al10Ni7Ti4Co2Fe1Y1 bulk amorphous alloy as the research object, by adding different mass fractions of low purity Zr raw materials (sponge Zr), a detailed study of the impurities on the super multi Zr based bulk amorphous alloy Forming ability, thermal stability, mechanical properties and corrosion resistance were studied in this paper. Firstly, impurities on the super multiple Zr based bulk amorphous alloy forming ability of non impact. In the supercooled liquid region width Delta Tx criterion based on different impurity content over multiple Zr based bulk amorphous alloy samples DSC analysis found that they are very close to the Tx, impurity content in super multi impact forming ability of Zr based bulk amorphous alloy. The arc melting after the diameter of 20 mm ingot also showed glassy fracture is typical in the cut, and XRD results showed that the crystallization degree is low, showing the good glass forming ability. Secondly, the different content of Zr sponge preparation of super multi Zr based bulk amorphous alloy thermal stability and crystallization behavior were studied further. Through the DSC curve analysis showed that thermal stability of impurities on the alloy The impact is not big, but will affect the super multi Zr based bulk amorphous alloy crystallization behavior, and with the increase of impurity content, the crystallization process is more complex, longer crystallization time. Complete crystallization products block of different impurity content of the amorphous alloy was found that impurity content does not affect the crystallization of the amorphous alloy the precipitates are mainly CuZr2, Cu10Zr7 and ZrAl phase structure. Finally, this paper analyzes the different content of Zr sponge preparation of super multi Zr based bulk amorphous alloy by mechanical and chemical properties of room temperature. Through the quasi-static compression test can know, super multi Zr based bulk amorphous alloy strength the content of impurity, the hardness is very high, with little change, but has different effects on different plastic impurity content of the alloy, low concentration impurity content does not make the alloy brittle, the plastic is not affected, but when the mass fraction of Zr sponge More than 80% plastic, up to 6.7%, is 3 times higher than pure material when preparing nano matrix. The impurity induced in-situ precipitation around 5 nm phase, leading to the plasticity of bulk amorphous alloys are greatly improved. In addition, high purity raw material preparation of super multi Zr based bulk amorphous alloy in after low temperature relaxation after plasticsignificantly increased, while the high impurity content super multi Zr based bulk amorphous alloy after low temperature relaxation after plastic decline. This may be because of high purity raw materials for the preparation of super multi Zr based bulk amorphous alloy in low temperature relaxation leads to the improvement of the no uniform composition, and super multiple Zr based bulk amorphous alloy in non nanocrystalline high impurity content decreases with the decrease in free volume. The electrochemical corrosion experiment shows that there is no significant influence over multiple corrosion potentials of Zr based bulk amorphous alloy impurities, means of impurities on the super multi Zr The corrosion resistance of the base bulk amorphous alloy has no obvious effect.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG139.8

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