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Title: Spatially-correlated Site Occupancy in the Nonstoichiometric Meta-stable ε -Al60Sm11 Phase during Devitrification of Al-10.2 at.% Sm Glasses

Journal Article · · Acta Materialia

A metastable ε-Al60Sm11 phase appears during the initial devitrification of as-quenched Al-10.2 at.% Sm glasses. The ε phase is nonstoichiometric in nature since Al occupation is observed on the 16f Sm lattice sites. Scanning transmission electron microscopic images reveal profound spatial correlation of Sm content on these sites, which cannot be explained by the “average crystal” description from Rietveld analysis of diffraction data. Thermodynamically favorable configurations, established by Monte Carlo (MC) simulations based on a cluster-expansion model, also give qualitatively different correlation functions from experimental observations. On the other hand, molecular dynamics simulations of the growth of ε-Al60Sm11 in undercooled liquid show that when the diffusion range of Sm is limited to ~4 Å, the correlation function of the as-grown crystal structure agrees well with that of the scanning transmission electronic microscopy (STEM) images. Furthermore, our results show that kinetic effects, especially the limited diffusivity of Sm atoms plays the fundamental role in determining the nonstoichiometric site occupancies of the ε-Al60Sm11 phase during the crystallization process.

Research Organization:
Ames Lab., Ames, IA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC02-07CH11358
OSTI ID:
1441002
Alternate ID(s):
OSTI ID: 1496402
Report Number(s):
IS-J-9660; PII: S1359645418303847
Journal Information:
Acta Materialia, Vol. 156, Issue none; ISSN 1359-6454
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 5 works
Citation information provided by
Web of Science

References (16)

Amorphous, nanoquasicrystalline and nanocrystalline alloys in Al-based systems journal December 1998
Eutectic-to-metallic glass transition in the Al–Sm system journal October 2011
Atomic-level structure and structure–property relationship in metallic glasses journal May 2011
Al-based amorphous alloys: Glass-forming ability, crystallization behavior and effects of minor alloying additions journal June 2017
Crystallization behaviour of AlSm amorphous alloys journal May 1994
Phase selection in Al–TM–RE alloys: nanocrystalline Al versus intermetallics journal May 2001
Asymmetric cation nonstoichiometry in spinels: Site occupancy in Co 2 ZnO 4 and Rh 2 ZnO 4 journal August 2011
The Monte Carlo Method journal September 1949
Cluster Approach to Order-Disorder Transformations in Alloys book January 1994
Generalized cluster description of multicomponent systems journal November 1984
GIBBS: isothermal-isobaric thermodynamics of solids from energy curves using a quasi-harmonic Debye model journal March 2004
First-principles phonon calculations of thermal expansion in Ti 3 SiC 2 , Ti 3 AlC 2 , and Ti 3 GeC 2 journal May 2010
A simple empirical N -body potential for transition metals journal July 1984
Development of interatomic potentials appropriate for simulation of devitrification of Al 90 Sm 10 alloy journal April 2015
Fast Parallel Algorithms for Short-Range Molecular Dynamics journal March 1995
Implementing molecular dynamics on hybrid high performance computers – short range forces journal April 2011

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