On the high glass-forming ability of Pt-Cu-Ni/Co-P-based liquids
On the high glass-forming ability of Pt-Cu-Ni/Co-P-based liquids
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DOI：
10.1016/j.actamat.2017.09.013
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发表时间：
2017-12-01
期刊：
影响因子：
9.4
通讯作者：
Gallino, Isabella
中科院分区：
文献类型：
--
作者：
Gross, Oliver;Riegler, Sascha S.;Gallino, Isabella
用量热法测定了Pt42.5Cu27Ni9.5P21和Pt 60 Cu 16 Co2 P22块体玻璃形成组分的连续晶化图和等温晶化图。在Pt42.5Cu27Ni9.5P21块状金属玻璃的情况下，可以通过在常规DSC中快速冷却来防止主晶相的形成。相比之下，对于类似的冷却条件下，在Pt 60 Cu 16 Co2 P22中的初级沉淀化合物的形成在常规DSC中不能被阻止，如在原位同步加速器X射线散射实验中也观察到的。这归因于临界过热，高于该临界过热，剩余结构溶解，导致过冷度急剧增加，类似于在Zr基BMG中观察到的。使用经典成核理论，结合热力学和动力学数据来模拟Pt42.5Cu27Ni9.P-51（21）的等温结晶数据，得到初级成核晶体和液体之间的界面能值为0.11 J/m（2）。该值比良好的Zr基玻璃形成剂的值高三倍，这表明界面能在Pt-P基系统的异常高的玻璃形成能力中起着关键作用，并补偿了脆弱的液体行为和结晶的大驱动力。(C)2017 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The continuous and isothermal crystallization diagrams of the Pt42.5Cu27Ni9.5P21 and the Pt60Cu16Co2P22 bulk glass forming compositions are determined using calorimetric experiments. In the case of the Pt42.5Cu27Ni9.5P21 bulk metallic glass, the formation of the primary crystalline phase can be prevented by rapid cooling in a conventional DSC. In contrast, for similar cooling conditions, the formation of the primary precipitating compound in Pt60Cu16Co2P22 cannot be prevented in a conventional DSC as also observed in in-situ synchrotron X-ray scattering experiments. This is attributed to a critical overheating, above which remaining structures dissolve, resulting in a drastic increase of the degree of undercooling, similar to what is observed in Zr-based BMGs. Using the classical nucleation theory, the combined thermodynamic and kinetic data are used to model the isothermal crystallization data for Pt42.5Cu27Ni9.P-51(21), yielding an interfacial energy value of 0.11 J/m(2) between the primary nucleating crystal and the liquid. This value is three times higher than the value for good Zr-based glass-formers, suggesting that the interfacial energy plays a pivotal role in the exceptionally high glass-forming ability of Pt-P-based systems and compensates for the fragile liquid behavior and the large driving force for crystallization. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.