Processing, Structure, and Properties of Amorphous Aluminum Alloys

228 Pages·2016·2.15 MB·English

by  Timothy Wayne Wilson

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Doctoral Dissertations Graduate School
5-2008
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Timothy Wayne Wilson
University of Tennessee - Knoxville
Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss
Part of the Materials Science and Engineering Commons
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Wilson, Timothy Wayne, "Processing, Structure, and Properties of Amorphous Aluminum Alloys. " PhD
diss., University of Tennessee, 2008.
https://trace.tennessee.edu/utk_graddiss/354
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To the Graduate Council:
I am submitting herewith a dissertation written by Timothy Wayne Wilson entitled "Processing,
Structure, and Properties of Amorphous Aluminum Alloys." I have examined the final electronic
copy of this dissertation for form and content and recommend that it be accepted in partial
fulfillment of the requirements for the degree of Doctor of Philosophy, with a major in Materials
Science and Engineering.
Hahn Choo, Major Professor
We have read this dissertation and recommend its acceptance:
Peter Liaw, Takeshi Egami, David Joy
Accepted for the Council:
Carolyn R. Hodges
Vice Provost and Dean of the Graduate School
(Original signatures are on file with official student records.)
To the Graduate Council:

I am submitting herewith a dissertation written by Timothy Wayne Wilson Jr. entitled
"Processing, Structure, and Properties of Amorphous Aluminum Alloys.” I have examined the
final electronic copy of this dissertation for form and content and recommend that it be
accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy,
with a major in Materials Science and Engineering.

____________________________
Hahn Choo, Major Professor

We have read this thesis
and recommend its acceptance:

Peter Liaw
_________________________

Takeshi Egami
___________________

David Joy
__________________________

Accepted for the Council:

Carolyn R. Hodges
___________________________
Vice Provost and Dean of the
Graduate School

(Original signatures are on file with official student records)
PROCESSING, STRUCTURE, AND PROPERTIES OF
AMORPHOUS ALUMINUM ALLOYS

A Dissertation
Presented for the
Doctor of Philosophy
Degree
The University of Tennessee, Knoxville

Timothy Wayne Wilson Jr.
May 2008
Dedication

To my wife, Ashley Wilson, and all of my family, thank you for providing me
inspiration and support.
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Acknowledgements
I appreciate the help that many people have given me during the course of my
Ph.D. study. My advisor, Dr. Hahn Choo has given me scientific guidance, inspiration,
and motivation, and he has provided me the opportunity to further develop my academic
and professional capability. I would like to thank my co-advisor Dr. Peter Liaw for his
kind encouragement and advice. I would also like to thank my other committee members,
Dr. Takeshi Egami and Dr. David Joy for their helpful advice and suggestions.
During this process many people have offered their kind advice, time, and
knowledge. I am thankful to all of our team members: Mrs. Elena Garlea, Dr. Wanchuck
Woo, Mr. Jinwoo Jeon, Dr. Kaixiang Tao, Dr. James Wall, Mr. Michael Benson, Mr. E-
Wen Huang, Dr. Gongyao Wang, Mr. Robert McDaniel, Ms. Zhenzhen Yu, Mr. Andrew
Chaung, and Mr. Soo-yeol Lee for all of their help. In addition, I am thankful to Dr. Cang
Fan, Dr. Wenhui Jiang, Dr. Wojtek Dmowski, and Dr. Honqi Li. Mrs. Carol Winn, Mr.
Douglas Fielden, and Mr. Frank Holiway have also made contributions for which I am
grateful.
My special thanks go to those at Los Alamos National Laboratory for giving me
the opportunity to work and learn from them. I am thankful to Dr. Donald Brown, Dr.
Bjorn Clausen, and Mr. Thomas Sisneros for all of their help and guidance.
This work is supported by the NSF International Materials Institutes (IMI)
Program under Contract DMR-0231320. This work benefited from use of the MUCAT
beamline a APS and beamline X14A of NSLS at BNL. The use of the APS was
supported by the U.S. DOE, Basic Energy Sciences, Office of Science, under Contract
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No.W-31-109-Eng-38 and MUCAT by Contract No.W-7405-Eng-82 through the Ames
Laboratory. Beamline X14A is sponsored by the Assistant Secretary for Energy
Efficiency and Renewable Energy, Office of Transportation Technologies, as part of the
High Temperature Materials Laboratory User Program, ORNL, managed by UT-Battelle,
LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725. This work also
benefited from the use of the Los Alamos Neutron Science Center at the Los Alamos
National Laboratory. This facility is funded by the US Department of Energy under
Contract W-7405-ENG-36.
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Abstract
Although research has been conducted on amorphous aluminum-based alloys,
most of the research has focused on melt-spun ribbons. There has been significantly less
research on mechanically alloyed amorphous powder even though mechanically alloyed
powder seems to have more potential for the production of bulk amorphous aluminum-
based alloys. In addition, there has not been adequate research conducted on the local
atomic structure of amorphous aluminum alloys, and a greater understanding of the
relationship between processing, structure, and properties is necessary.
In the following thesis, multiple investigations have been performed to
understand the structure, processing, and properties of aluminum-based amorphous alloys.
These studies sought to develop a methodology for the production of amorphous
aluminum alloys by mechanical alloying, understand how composition affects the glass-
forming ability, understand the crystallization and its effects on structure and properties,
and consolidate the mechanically alloyed powder and examine the resultant structure and
properties.
High-energy ball milling was used to synthesize aluminum-based alloys
containing amorphous and nanocrystalline phases to investigate the compositional effects
of transition metals (TM) on the amorphization and crystallization processes of the ball-
milled Al Y Fe TM alloys (TM = Ni, Co, Cu, and Fe) were investigated.
85 7 5 3
The local atomic structure of mechanically alloyed Al Y Fe and Al Y Fe Ti
85 7 8 83 7 8 2
were examined by high-energy synchrotron x-ray diffraction. Diffraction results showed
that Al Y Fe structure to be nanocrystalline, while Al Y Fe Ti is amorphous. The pair
85 7 8 83 7 8 2
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distribution function analyses revealed that local structure of Al Y Fe was dominated by
85 7 8
Al, Fe, and Al Y short range ordered regions. On the other hand, the local structure of
3
Al Y Fe Ti was comprised of Al, Al Fe, and Al Y short-range order regions, in which
83 7 8 2 6 3
the order extended for about 8 angstroms.
Efforts to consolidate the mechanically alloyed amorphous powder were made by
quasi-isostatic forging at different temperatures. Samples were also processed containing
different levels of coarse grain crystalline aluminum to evaluate the production of bi-
modal composites.
In addition to the research performed on amorphous aluminum alloys, research on
the mechanical behavior of the local atomic structure of a bulk metallic glass was
performed. The internal strain was measured for a Zr Nb Cu Ni Al BMG in-situ
57 5 15.4 12.6 10
by neutron diffraction.
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Table of Contents

Chapter I: Introduction.....................................................................................................1
1.1 Amorphous Aluminum-based Alloys…………………………………………………1
1.2 Synthesis and Characterization………………………………………………………..3
1.3 Powder Consolidation…………………………………………………………………5
1.4 Total Scattering………………………………………………………………………..6
1.5 Motivation of the Research……………………………………………………………7
Chapter II: Literature Review…………………………………………………………..9
Part I: Bulk Metallic Glasses…........................................................................................9
2.1 History………………………………………………………………………………....9
2.2 Properties…………………………………………………………………………….10
2.3 Applications………………………………………………………………………….10
2.4 Glass Formation……………………………………………………………………...11
2.4.1 Glass-Forming Ability (GFA)……………………………………………...11
2.4.2 Metallic Glass Forming Criterion………………………………………….12
2.5 Compositions………………………………………………………………………...13
2.6 Processing……………………………………………………………………………14
2.6.1 Rapid Solidification………………………………………………………..15
2.6.2 Melt Spinning……………………………………………………………...16
2.6.3 Metallic Mold Casting……………………………………………………..17
2.6.4 Deformation………………………………………………………………..18
2.7 Structure……………………………………………………………………………...18
2.7.1 General Structure…………………………………………………………..18
2.7.2 Local Atomic Structure…………………………………………………….21
2.8 Thermal Stability…………………………………………………………………….23
2.8.1 Glass Transition……………………………………………………………23
2.8.2 Structural Relaxation………………………………………………………25
2.8.3 Crystallization……………………………………………………………...26
2.8.4 Nanocrystallization………………………………………………………...27
2.9 Local Structure of Metallic Glasses………………………………………………….29
2.10 Conclusions…………………………………………………………………………31
Part II: Amorphous Aluminum Alloys………………………………………………..32
2.11 History………………………………………………………………………………32
2.12 Glass Formation…………………………………………………………………….33
2.13 Amorphization Mechanisms………………………………………………………..34
2.14 Systems……………………………………………………………………………..35
2.15 Processing…………………………………………………………………………..35
2.15.1 Rapid Solidification………………………………………………………36
2.15.2 Metallic Mold Casting……………………………………………………37
2.15.3 Deformation………………………………………………………………37
2.16 Structure…………………………………………………………………………….38
2.17 Weak (marginal) glass former vs. BMGs…………………………………………..39
2.18 Thermal Stability…………………………………………………………………...41
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