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Title: An abnormal meta-stable nanoscale eutectic reaction revealed by in-situ observations

Abstract

Phase selection and growth of materials far from equilibrium provides fertile ground for novel phases and morphologies since a multitude of different pathways may be energetically accessible. In this study, a complex metastable devitrification of Al 60Sm 11 (ε-phase) from its amorphous precursor is discovered using a combination of in-situ high-energy X-ray diffraction (HEXRD), providing insight into the average bulk behavior, and in-situ aberration corrected scanning transmission electron microscopy, revealing the atomic scale mechanisms of growth and their dynamics. We have found that non-equilibrium chemical partitioning disrupts the nominal planer growth by formation of nanoscale Al enriched regions inhomogeneously segregated at the ε/glass interface, to locally balance the compositionally dependent driving force and the associated diffusional burden imposed on its grain growth. These Al-rich regions form fcc-Al-rich nanocrystallites epitaxially with the ε-phase, modifying ε/glass interface mobility and creating a crenulated growth front. As a result, this new mechanism offers a pathway for fabricating alloy structures with nanoprecipitate dispersions through a meta-stable phase transition.

Authors:
 [1]; ORCiD logo [1];  [1];  [1];  [1];  [1];  [2];  [1]
  1. Ames Lab., Ames, IA (United States)
  2. Ames Lab. and Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1483408
Report Number(s):
IS-J-9809
Journal ID: ISSN 1359-6454; PII: S1359645418309030
Grant/Contract Number:  
AC02-07CH11358; AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 164; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Metastable phase transition; In situ aberration-corrected transimission electron microscopy; In-situ high-energy X-ray diffraction

Citation Formats

Zhou, Lin, Meng, Fanqiang, Zhou, Shihuai, Sun, Kewei, Kim, TaeHoon, Ott, Ryan, Napolitano, Ralph, and Kramer, Matthew J. An abnormal meta-stable nanoscale eutectic reaction revealed by in-situ observations. United States: N. p., 2018. Web. doi:10.1016/j.actamat.2018.11.027.
Zhou, Lin, Meng, Fanqiang, Zhou, Shihuai, Sun, Kewei, Kim, TaeHoon, Ott, Ryan, Napolitano, Ralph, & Kramer, Matthew J. An abnormal meta-stable nanoscale eutectic reaction revealed by in-situ observations. United States. doi:10.1016/j.actamat.2018.11.027.
Zhou, Lin, Meng, Fanqiang, Zhou, Shihuai, Sun, Kewei, Kim, TaeHoon, Ott, Ryan, Napolitano, Ralph, and Kramer, Matthew J. Wed . "An abnormal meta-stable nanoscale eutectic reaction revealed by in-situ observations". United States. doi:10.1016/j.actamat.2018.11.027.
@article{osti_1483408,
title = {An abnormal meta-stable nanoscale eutectic reaction revealed by in-situ observations},
author = {Zhou, Lin and Meng, Fanqiang and Zhou, Shihuai and Sun, Kewei and Kim, TaeHoon and Ott, Ryan and Napolitano, Ralph and Kramer, Matthew J.},
abstractNote = {Phase selection and growth of materials far from equilibrium provides fertile ground for novel phases and morphologies since a multitude of different pathways may be energetically accessible. In this study, a complex metastable devitrification of Al60Sm11 (ε-phase) from its amorphous precursor is discovered using a combination of in-situ high-energy X-ray diffraction (HEXRD), providing insight into the average bulk behavior, and in-situ aberration corrected scanning transmission electron microscopy, revealing the atomic scale mechanisms of growth and their dynamics. We have found that non-equilibrium chemical partitioning disrupts the nominal planer growth by formation of nanoscale Al enriched regions inhomogeneously segregated at the ε/glass interface, to locally balance the compositionally dependent driving force and the associated diffusional burden imposed on its grain growth. These Al-rich regions form fcc-Al-rich nanocrystallites epitaxially with the ε-phase, modifying ε/glass interface mobility and creating a crenulated growth front. As a result, this new mechanism offers a pathway for fabricating alloy structures with nanoprecipitate dispersions through a meta-stable phase transition.},
doi = {10.1016/j.actamat.2018.11.027},
journal = {Acta Materialia},
number = C,
volume = 164,
place = {United States},
year = {Wed Nov 14 00:00:00 EST 2018},
month = {Wed Nov 14 00:00:00 EST 2018}
}

Journal Article:
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