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Effects of Dopant Additions on the High Temperature Oxidation Behavior of Nickel-Based Alumina- Forming Alloys

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Effects of Dopant Additions on the High Temperature Oxidation Behavior of Nickel-Based Alumina- Forming Alloys Effects of Dopant Additions on the High Temperature Oxidation Behavior of Nickel-based Alumina- forming Alloys by Talia L. Barth A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Materials Science and Engineering) in the University of Michigan 2020 Doctoral Committee: Professor Emmanuelle Marquis, Chair Assistant Professor John Heron Professor Krishna Garikipati Professor Alan Taub Talia L. Barth [email protected] ORCID iD: 0000-0001-8266-7447 © Talia L. Barth 2020 ACKNOWLEDGEMENTS I would like to first offer my heartfelt thanks to my advisor, Professor Emmanuelle Marquis, without whom this work would not have been possible. Her exceptional mentorship has had an immense impact on my development as a researcher and a person, and her support and guidance along my journey have been invaluable. I would also like to express my appreciation for the rest of my committee, Professor Alan Taub, Assistant Professor John Heron, and Professor Krishna Garikipati for providing valuable advice and support for the completion of this work. I am grateful to the staff at the Michigan Center for Materials Characterization (MC)2, especially to Allen Hunter, Bobby Kerns, Haiping Sun, and Nancy Muyanja whose training enabled me to work confidently on the characterization instruments essential to this dissertation, and were always eager to lend their expertise with data collection and analysis. My colleagues in the Marquis group over the years were also important to this work and to my professional and personal development. I would like to thank Kevin Fisher, Ellen Solomon, Elaina Reese, and Peng-Wei Chu for getting me up to speed in the lab and for being there as mentors and friends in my first years as a grad student. Many thanks also to Li-Jen Yu and Kathleen Chou, whose support and friendship were invaluable as we pursued our Ph.Ds together. Finally, a very special thanks to my friends and family, whose support enabled me to push through the toughest challenges over the years. To all of the friends I’ve connected with playing ultimate, I am so glad to be a part of such an amazing community, and feel lucky to have ii met some of my best friends here in Michigan. My parents, Kathleen and Matthew Barth, have given me endless encouragement and support in all that I choose to do, and for that I am forever grateful. I would also like to thank my brother, Trevor, whose friendship means the world to me. Lastly, I must thank Eric, who remained a constant source of positivity and was there for me during the most difficult parts of the last couple years. I feel very lucky to have you in my life. For all of these people, and more who influenced me along the way, thank you. iii TABLE OF CONTENTS ACKNOWLEDGEMENTS ............................................................................................................ ii LIST OF TABLES ......................................................................................................................... vi LIST OF FIGURES ...................................................................................................................... vii LIST OF APPENDICES ............................................................................................................... xv ABSTRACT ................................................................................................................................. xvi CHAPTER 1: Introduction ............................................................................................................. 1 1.1 Background and Motivation .................................................................................................. 1 1.2 Thesis Structure ..................................................................................................................... 3 CHAPTER 2: Literature Review .................................................................................................... 4 2.1 Overview ............................................................................................................................... 4 2.1.1 Oxide Phase Stability...................................................................................................... 5 2.1.2 Oxide Growth Rate ......................................................................................................... 6 2.1.3 Oxide Stress Development and Adherence .................................................................... 8 2.2 Transient Oxidation of Alumina-forming Alloys ................................................................. 9 2.2.1 Alumina Metastable Phases and Transformation to α-Al2O3 ......................................... 9 2.2.2 Metastable Alumina Formation during Thermal Oxidation of NiAl ............................ 12 2.2.3 Dopant Effects on Alumina Transformation ................................................................ 21 2.3 Steady-State Oxidation of NiAl .......................................................................................... 24 2.3.1 Alumina Microstructure and Oxidation Kinetics ......................................................... 24 2.3.2 The Reactive Element Effect ........................................................................................ 34 2.3.3 Alumina Growth Mechanisms ...................................................................................... 35 2.3.4 Al/O Transport and Dopant Segregation ...................................................................... 40 2.3.5 Dopant Optimization and Co-Doping ........................................................................... 45 2.3.6 Stress Development in Alumina Scales ........................................................................ 47 2.4 Summary of Major Findings, Research Gaps, and Motivation for this Dissertation .......... 52 CHAPTER 3: Effects of Minor Alloying Elements on Alumina Transformation During the Transient Oxidation of β-NiAl ...................................................................................................... 58 3.1 Introduction ......................................................................................................................... 58 3.2 Experimental Details ........................................................................................................... 60 3.3 Results ................................................................................................................................. 62 3.4 Discussion ........................................................................................................................... 75 3.5 Conclusions ......................................................................................................................... 79 CHAPTER 4: Dopant Effects on Transport Through Thermally Grown α-Al2O3 Scales on NiAl ....................................................................................................................................................... 81 4.1 Introduction ......................................................................................................................... 81 4.2 Experimental Details ........................................................................................................... 84 4.2.1 Sample Preparation ....................................................................................................... 84 iv 4.2.2 Outward Aluminum Transport Experiment .................................................................. 85 4.2.3 Inward Oxygen Transport Experiment ......................................................................... 87 4.2.4 Additional Characterization .......................................................................................... 88 4.3 Results ................................................................................................................................. 88 4.4 Discussion ......................................................................................................................... 102 4.5 Conclusions ....................................................................................................................... 108 CHAPTER 5: The Effect of Ti on the Early Stages of Oxidation of an Alumina-Forming NiCrAl Alloy ........................................................................................................................................... 110 5.1 Introduction ....................................................................................................................... 110 5.2 Experimental Procedure .................................................................................................... 112 5.3 Results ............................................................................................................................... 114 5.4 Discussion ......................................................................................................................... 123 5.5 Conclusions ....................................................................................................................... 127 CHAPTER 6: Conclusions and Future Directions...................................................................... 128 6.1 Dopant Effects on Transient Oxidation ............................................................................. 128 6.1.1 Research Opportunities............................................................................................... 130 6.2 Dopant Effects on Steady-State
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