Composition-dependent stability of the medium-range order responsible for metallic glass formation
- Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
- Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States); Univ. of Science and Technology, Hefei (Republic of China)
- Ames Lab., Ames, IA (United States)
The competition between the characteristic medium-range order corresponding to amorphous alloys and that in ordered crystalline phases is central to phase selection and morphology evolution under various processing conditions. We examine the stability of a model glass system, Cu–Zr, by comparing the energetics of various medium-range structural motifs over a wide range of compositions using first-principles calculations. Furthermore, we focus specifically on motifs that represent possible building blocks for competing glassy and crystalline phases, and we employ a genetic algorithm to efficiently identify the energetically favored decorations of each motif for specific compositions. These results show that a Bergman-type motif with crystallization-resisting icosahedral symmetry is energetically most favorable in the composition range 0.63 < xCu < 0.68, and is the underlying motif for one of the three optimal glass-forming ranges observed experimentally for this binary system (Li et al., 2008). This work establishes an energy-based methodology to evaluate specific medium-range structural motifs which compete with stable crystalline nuclei in deeply undercooled liquids.
- Research Organization:
- Ames Laboratory (AMES), Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-07CH11358
- OSTI ID:
- 1239834
- Alternate ID(s):
- OSTI ID: 1556277
- Report Number(s):
- IS-J 8912; PII: S1359645414006521
- Journal Information:
- Acta Materialia, Vol. 81, Issue C; ISSN 1359-6454
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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