Cu8Zr3和Cu10Zr7相中存在Cu8Zr5和Cu6Zr5团簇结构，它们与Cu-Zr系的两个深共晶点Cu61.8Zr38.2和Cu56Zr44对应. Cu64Zr36是Cu-Zr二元系具有最大玻璃形成能力的成分点. 依据形成块体非晶的“变电子浓度线判据”，以Cu64Zr36, Cu61.8Zr38.2和Cu56Zr44 3个二元成分为出发点，以Nb元素为第三组元，建立变电子浓度线(Cu64Zr36)100-xNbx, (Cu61.8Zr38.2)100-xNbx和 (Cu56Zr44)100-xNbx. 采用分步熔炼法，由铜模吸铸法制备直径为3 mm的合金棒. 块体非晶的玻璃形成区及玻璃形成能力由XRD和热分析确定. 结果表明, 添加少量Nb(原子分数, x≤3)可以显著提高Cu-Zr二元系的玻璃形成能力. 具有最大Tg/Tl值(0.626)的成分Cu60.3Zr37.2Nb2.5位于具有Cu8Zr5团簇和最深共晶点的Cu61.8Zr38.2向第三组元Nb的连线上. 结合Cu-Zr二元体系的团簇结构讨论了Cu-Zr-Nb系块体非晶的形成.
Two atomic clusters, Cu8Zr5 and Cu6Zr5 derived from the Cu8Zr3 and Cu10Zr7 phase structures, correspond to two deep eutectic compositions of Cu61.8Zr38.2 and Cu56Zr44. Cu64Zr36 is the best glass-forming composition in the Cu-Zr binary system. Three e/a-variant composition lines (Cu64Zr36)100-xNbx, (Cu61.8Zr38.2)100-xNbx and (Cu56Zr44)100-xNbx were constructed in the Cu--Zr--Nb system by linking these three specific compositions with the third constitute Nb. The pure Zr and Nb elements were first melted into interalloys, then the interalloys were melted with Cu, and finally alloy bars with diameter of 3 mm were prepared by copper mould suction casting. Minor Nb additions (atomic fraction, x≤3) can improve remarkably the glass forming abilities of the Cu-Zr alloys. The optimum composition Cu60.3Zr37.2Nb2.5 with the highest Tg/Tl =0.626 is located on the e/a -variant line linking the third element Nb and Cu8Zr5 icosahedral cluster and Cu61.8Zr38.2 which possess the deepest eutectic point. The glass formation relative to clusters in Cu-Zr system is also discussed.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] | |
| [9] | |
| [10] | |
| [11] |
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%