物理学报2016，Vol.65Issue(6)：266-275,10.DOI:10.7498/aps.65.066401
二十面体团簇的遗传：一个与快凝Cu56Zr44合金玻璃形成能力有关的动力学参数∗
Heredity of icosahedrons：a kinetic parameter related to glass-forming abilities of rapidly solidified Cu56Zr44 alloys
摘要
Abstract
To explore the origin of glassy transition and glass-forming abilities (GFAs) of transition metal-transition metal alloys from the microstructural point of view, a series of molecular dynamics simulation for the rapid solidification processes of liquid Cu56Zr44alloys at various cooling rates γ and pressures P are performed by using a LAMPS program. On the basis of Honeycutt-Andersen bond-type index (ijkl), we propose an extended cluster-type index (Z, n/(ijkl)) method to characterize and analyze the microstructures of the alloy melts as well as their evolution in the rapid solidification. It is found that the majority of local atomic configurations in the rapidly solidified alloy are (12 12/1551) icosahedra, as well as (12 8/1551 2/1541 2/1431) and (12 2/1441 8/1551 2/1661) defective icosahedra, but no relationship can be seen between their number N(300 K) and the glassy transition temperature Tg of rapidly solidified Cu56Zr44alloys. By an inverse tracking of atom trajectories from low temperatures to high temperatures the configuration heredity of icosahedral clusters in liquid is discovered to be an intrinsic feature of rapidly solidified alloys; the onset of heredity merely emerges in the super-cooled liquid rather than the initial alloy melt. Among these the (12 12/1551) standard icosahedra inherited from the super-cooled liquids at Tm–Tg is demonstrated to play a key role in the formation of Cu56Zr44 glassy alloys. Not only is their number Np300 K←Tg inherited from Tg to 300 K closely related to the GFA of rapidly solidified Cu56Zr44 alloys, but a good correspondence of the onset temperatures of heredity (Tonset) with the reduced glass transition temperature (Trg=Tg/Tm) can be also observed. As for the influence ofγ and P on the glassy transition, a continuous tracking of descendible icosahedra reveals that the high GFA of rapidly solidified Cu56Zr44 alloys caused by bigγ and P can be attributed to their elevated inheritable fraction (fp and ftotal) above Tg.关键词
快速凝固/分子动力学/玻璃形成能力/二十面体团簇Key words
rapid solidification/molecular dynamics/glass-forming ability/icosahedral clusters引用本文复制引用
邓永和,大东,彭超,韦彦丁,赵瑞,彭平..二十面体团簇的遗传：一个与快凝Cu56Zr44合金玻璃形成能力有关的动力学参数∗[J].物理学报,2016,65(6):266-275,10.基金项目
国家自然科学基金(批准号:51071065,51428101)和湖南省自然科学基金(2013JJ6070,2015JJ5033)资助的课题.* Project supported by the National Natural Science Foundation of China (Grant Nos.51071065,51428101), and the Natural Science Foundation of Hunan Province, China (Grant Nos.2013JJ6070,2015JJ5033) （批准号:51071065,51428101）
