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Unequal effect of thermodynamics and kinetics on glass forming ability of Cu–Zr alloys

Authors :
Shraddha Ganorkar
Yun-Hee Lee
Sooheyong Lee
Yong Chan Cho
Takehiko Ishikawa
Geun Woo Lee
Source :
AIP Advances, Vol 10, Iss 4, Pp 045114-045114-10 (2020)
Publication Year :
2020
Publisher :
AIP Publishing LLC, 2020.

Abstract

The glass forming ability (GFA) of Cu–Zr alloys has been still ambiguous, due to incomplete or lacking thermophysical properties of Cu–Zr liquids in supercooled and stable states, although tremendous effort has been devoted. We provide here the comprehensive thermophysical properties of Cu–Zr liquids, such as undercoolability, density, viscosity, fusion enthalpy, temperature–time-transformation (TTT) diagram, and crystal–liquid interfacial free energy. Three compositions, Cu64Zr36, Cu56Zr44, and Cu50Zr50, show distinctive anomalies in undercoolability, nose time in TTT, and crystal–liquid interfacial free energy, but not in density and viscosity in supercooled and stable liquid states. The anomalies reflect that the GFA is dominantly governed by thermodynamics rather than kinetics in these bulk metallic glasses (BMGs). In addition, we find that positions of nose temperatures in the TTT curves are below 1/2 (Tg + Tl), which implies unequal contribution of thermodynamics and kinetics. We discuss that empirical GFA parameters cannot explain the glass formation of Cu–Zr alloys due to the unequal contribution, and the Turnbull GFA criterion (Trg = Tg/Tl) is valid for the equal contribution of the two effects. The present experimental findings shed light on the ongoing debate about the GFA criterion of Cu–Zr BMGs.

Subjects

Subjects :
Physics
QC1-999

Details

Language :
English
ISSN :
21583226
Volume :
10
Issue :
4
Database :
Directory of Open Access Journals
Journal :
AIP Advances
Publication Type :
Academic Journal
Accession number :
edsdoj.33e965414ecd456a90877c8fbb8c790a
Document Type :
article
Full Text :
https://doi.org/10.1063/5.0002784