Critical Evaluation and Thermodynamic Modeling of High Alloy Fe-Mn-Al-Si-C-P System Zhimin You Department of Mining and Materials Engineering McGill University, Montreal, Quebec, Canada August 2020 A thesis submitted to McGill University in partial fulfilment of the requirements of the degree of Doctorate of Philosophy ©Zhimin You, 2020 Dedication To my parents, my brother, and my sister in China Tables of Content Abstract .......................................................................................................................................... 6 Résumé ........................................................................................................................................... 8 Acknowledgements ..................................................................................................................... 10 Preface and Contributions of Authors ...................................................................................... 12 List of Figures .............................................................................................................................. 14 List of Tables ............................................................................................................................... 20 List of Abbreviations and Symbols ........................................................................................... 22 Chapter 1: Introduction ............................................................................................................. 26 1.1 Background ......................................................................................................................... 26 1.2 Objective ............................................................................................................................. 27 1.3 CALPHAD Method............................................................................................................. 28 1.4 Organization of the Thesis .................................................................................................. 30 References ................................................................................................................................. 31 Chapter 2: Thermodynamic Modeling ..................................................................................... 34 2.1 Critical Evaluation and Optimization .................................................................................. 34 2.2 FactSage Software ............................................................................................................... 37 2.3 Thermodynamic Models ..................................................................................................... 39 2.3.1 Pure Elements and Stoichiometric Compounds ........................................................... 39 2.3.2 Liquid Solution ............................................................................................................. 42 2.3.3 Solid Solutions .............................................................................................................. 49 Reference ................................................................................................................................... 52 Chapter 3: Critical Evaluation and Thermodynamic Optimization of the Fe-P System ..... 54 Abstract ..................................................................................................................................... 54 3.1. Introduction ........................................................................................................................ 55 1 3.2 Thermodynamic Models ..................................................................................................... 57 3.2.1 Pure Elements and Stoichiometric Compounds ........................................................... 57 3.2.2 Liquid Solution ............................................................................................................. 59 3.2.3 Solid Solutions .............................................................................................................. 61 3.3 Critical Evaluation and Thermodynamic Optimization ...................................................... 62 3.3.1 Phase Diagram .............................................................................................................. 62 3.3.2 Thermodynamic Properties of Iron Phosphides ........................................................... 67 3.3.3 Thermodynamic Properties of Liquid Solution ............................................................ 76 3.3.3.1 Dissolution of Phosphorus in Liquid Fe from Gas Phase ...................................... 77 3.3.3.2 Activity of Fe and P in Liquid Solution ................................................................. 80 3.3.3.3 Enthalpy and Gibbs Energy of Mixing .................................................................. 86 3.4 Application of Optimized Database to Dephosphorization Calculation for Liquid Fe ....... 87 3.5 Summary ............................................................................................................................. 90 Acknowledgments ..................................................................................................................... 91 References ................................................................................................................................. 91 Chapter 4: Thermodynamic Optimization of the Mn-P and Fe-Mn-P Systems ................... 99 Abstract ..................................................................................................................................... 99 4.1. Introduction ...................................................................................................................... 100 4.2. Thermodynamic Models .................................................................................................. 102 4.2.1 Pure Elements and Stoichiometric Compounds ......................................................... 102 4.2.2 Solid Solutions ............................................................................................................ 103 4.2.3 Liquid Solution ........................................................................................................... 104 4.3 Critical Evaluation and Thermodynamic Optimization .................................................... 108 4.3.1 The Fe-P and Fe-Mn System ...................................................................................... 111 4.3.2 The Mn-P System ....................................................................................................... 113 4.3.2.1 Phase Diagram ..................................................................................................... 113 4.3.2.2 Liquid Solution .................................................................................................... 114 4.3.2.3 Stoichiometric Manganese Phosphides ................................................................ 118 2 4.3.3 The Fe-Mn-P System .................................................................................................. 127 4.3.3.1 Phase Diagram ..................................................................................................... 128 4.3.3.2 Thermodynamic Property of Liquid Solution ...................................................... 136 4.3.3.3 Predicted Phase Diagrams of the Fe-Mn-P System ............................................. 141 4.3.3.4 Improvements of Present Optimization Compared to Previous Assessments ..... 144 4.4 Summary ........................................................................................................................... 145 Acknowledgments ................................................................................................................... 145 References ............................................................................................................................... 146 Chapter 5: Critical Evaluation and Thermodynamic Optimization of the Al-P and Fe-Al-P Systems ....................................................................................................................................... 155 Abstract ................................................................................................................................... 155 5.1 Introduction ....................................................................................................................... 156 5.2. Thermodynamic Models .................................................................................................. 158 5.2.1 Pure Elements and Stoichiometric Compounds ......................................................... 158 5.2.2 Solid Solutions ............................................................................................................ 159 5.2.2.1 FCC_A1 Solid Solutions ...................................................................................... 160 5.2.2.2 Disordered/Ordered BCC Solid Solutions ........................................................... 161 5.2.2.3 Other Solid Solutions (Al8Fe5, Al13Fe4, Me3P, Me2P) ......................................... 162 5.2.3 Liquid Solution ........................................................................................................... 163 5.3 Critical Evaluation and Thermodynamic Optimization .................................................... 166 5.3.1 The Fe-P and Fe-Al