Michigan Technological University Digital Commons @ Michigan Tech Dissertations, Master's Theses and Master's Dissertations, Master's Theses and Master's Reports - Open Reports 2014 Nano-engineering of composite material via reactive mechanical alloying/milling (RMA/M) Edward Andrew Laitila Michigan Technological University Follow this and additional works at: https://digitalcommons.mtu.edu/etds Part of the Materials Science and Engineering Commons Copyright 2014 Edward Andrew Laitila Recommended Citation Laitila, Edward Andrew, "Nano-engineering of composite material via reactive mechanical alloying/milling (RMA/M)", Dissertation, Michigan Technological University, 2014. https://doi.org/10.37099/mtu.dc.etds/949 Follow this and additional works at: https://digitalcommons.mtu.edu/etds Part of the Materials Science and Engineering Commons Ǧ Ȁ ȋȀȌ By Edward Andrew Laitila A DISSERTATION Submitted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY In Materials Science and Engineering MICHIGAN TECHNOLOGICAL UNIVERSITY 2014 © 2014 Edward A. Laitila This dissertation has been approved in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY in Materials Science and Engineering. Department of Materials Science and Engineering Dissertation Advisor: Dr. Donald E. Mikkola Committee Member: Dr. Stephen L. Kampe Committee Member: Dr. Walter W. Milligan Committee Member: Dr. Michael E. Mullins Department Chair: Dr. Stephen L. Kampe Dedication “To my father, who passed away days after my defense, whom while not formally educated was a very intelligent man, who taught me independence, showing me how hard work pays off, and how to work with my hands……..thank you, for building the foundation that lead me to a passion I enjoy, your quick wit, and critical thinking skills rival anyone.” “To a person in my life who I developed such a special relationship with, that most never get to experience in their lifetime…this work is also dedicated to my supervisor, my teacher, my colleague, my advisor, my mentor, and more importantly my friend Dr. Donald E. Mikkola, who also taught me three very important words: think about it!” “Lastly and most importantly, I finally dedicate this work to my lovely wife, whose compassion and understanding during this long ordeal, allowed me to complete this work as a side part or our life…..without your love, support, and encouragement, this would have never happened.” Table of Contents Approval Page .................................................................................................................... 2 Dedication........................................................................................................................... 3 List of Figures .................................................................................................................... 4 List of Tables .................................................................................................................... 11 Acknowledgements ........................................................................................................... 13 Abstract ............................................................................................................................. 14 I. Introduction ............................................................................................................. 15 A. Chromium-Modified Titanium Trialuminide................................................................... 16 B. Strengthening Mechanisms Investigated .......................................................................... 19 1. Grain Size Refinement ............................................................................................ 20 2. Dispersion Strengthening ........................................................................................ 23 C. Polycrystalline Materials .................................................................................................... 25 1. Grain Boundary Structure ....................................................................................... 26 2. Nanostructure Materials .......................................................................................... 30 3. Severe Deformation Processing .............................................................................. 34 D. Mechanical Alloying ............................................................................................................ 39 1. Reactive Mechanical Alloying/Milling (RMA/M) .................................................. 43 2. MA of Titanium-Aluminum .................................................................................... 44 3. Modeling of Mechanical Alloying .......................................................................... 46 E. Chromium-Modified Titanium Trialuminide Matrix Composites ................................. 52 F. Research Genesis ................................................................................................................. 53 II. Experimental............................................................................................................57 A. Experimental Procedure ..................................................................................................... 57 1. Production of Cubic Trialuminide Powder – Reading Alloy .................................. 57 2. Production of Cubic Trialuminide Powder - Master Alloy ..................................... 58 3. Milling Apparatus ................................................................................................... 59 4. Thermal Treatment of Powders ............................................................................... 59 5. Characterization ...................................................................................................... 61 6. Properties Explored ................................................................................................. 79 B. Reactive Mechanical Alloying/Milling (RMA/M) Processing Experiments ................... 82 1. Reactive Mechanical Milling (RMM) of Pre-Alloyed Powders with Fixed Excess Titanium Addition in an Argon Atmosphere ........................................................................................... 83 4 2. Reactive Mechanical Alloying (RMA) of Elemental Powders with Excess Titanium in an Argon Atmosphere .......................................................................................................................... 85 3. Reactive Mechanical Milling (RMM) of Pre-Alloyed Powders with Systematic Increases in Excess Titanium and RMM Time in an Argon Atmosphere ............................................... 87 C. Consolidation of RMM and MM Powders by Cold Isostatic Press (CIP) and Hot Isostatic Press (HIP) Processing ................................................................................................. 88 III. Experimental Results of the Powder Processing by Reactive Mechanical Alloying/Milling................................................................................................................93 A. Reactive Mechanical Milling (RMM) of Pre-Alloyed Powders with Fixed Excess Titanium RMMXh9TiAr Series ................................................................................................. 93 1. As-Milled Powders .................................................................................................. 93 2. X-ray Powder Diffraction Analysis of Annealed Powder ..................................... 113 3. X-ray Powder Diffraction Intensity Analysis ........................................................ 114 4. Macrostructure of Powders ................................................................................... 119 B. Reactive Mechanical Alloying (RMA) of RMA20h8.2TiAr Elemental Powders of Al66Cr9Ti25 with Excess Titanium in an Argon Atmosphere .................................................. 133 1. X-ray Power Diffraction Phase Analysis of As-Milled and Annealed Powder ..... 133 2. Phase Volume Fractions ........................................................................................ 135 3. Lattice Parameters ................................................................................................. 137 4. Peak Broadening Analysis of Profile Fit X-ray Diffraction Peaks by the Warren- Averbach Fourier Method...................................................................................................................... 139 C. Results from Reactive Mechanical Milling (RMM) of Pre-Alloyed Powders with Systematic Increases in Excess Titanium in an Argon Atmosphere ..................................... 140 D. Results from Consolidated Materials .............................................................................. 141 1. Characterization .................................................................................................... 141 2. Properties of Consolidated Materials .................................................................... 170 IV. Discussion..............................................................................................................188 A. Nano-Scale Polycrystalline Materials Produced by Severe Deformation .................... 190 1. Structural Characterization of the Nanometer-Scale Powders Produced by the RMA/M Process 191 2. Nano-Scale Grain Boundary Structure .................................................................. 217 B. The Reactive Mechanical Alloying/Milling