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70-6859 RATLIFF, John Leigh, 1936 This dissertation has been microfilmed exactly as received 70-6859 RATLIFF, John Leigh, 1936- RE ACTION-DIFFUSION IN A METAL-NONMETAL BINARY SYSTEM AND THE MULTICOMPONENT SYSTEMS Ti/SiC AND Ti-6Al-4V/SiC. The Ohio State University, Ph.D., 1969 Engineering, metallurgy University Microfilms, Inc., Ann Arbor, Michigan REACTION—DIFFUSION IN A METAL-NONMETAL BINARY SYSTEM AND THE MULTICOMPONENT SYSTEMS Ti/SiC AND Ti-6Al-4V/SiC DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By John Leigh Ratliff, Met.E., M.S. *********** The Ohio State University 1969 Approved by Adviser Department of Metallurgical Engineering Dedicated to Mary Ann ACKNOWLEDGMENTS First, I would like to acknowledge my adviser, Dr. G. W. Powell, whose continuous interest and willing­ ness to discuss the results of this work as it progressed were most appreciated. Recognition is also extended to Dr. R. A. Rapp whose advice and contribution of time spent in informative discussions were appreciated. Recognition is given to Mr. D. E. Price of the Battelle Memorial Institute for helpful experimental suggestions and for assistance in performing high- temperature, vacuum annealing and sintering operations. Dr. H. D. Colson of The Ohio State University Department of Mathematics is deserving of special thanks for his helpful suggestions pertaining to the numerical solution of differential equations. Appreciation is extended to Mr. R. 0. Slonaker for preparing the computer program which performed the absorption corrections on the electron-microprobe analyses. Appreciation is also extended to Mr. Neal Farrar and Mr. Ross Justus for their excellent suggestions and work which was performed in relation to the design and construction of experimental equipment. Finally, I would like to acknowledge the Metals and Ceramics Division, Air Force Materials Laboratory, Wright-Patterson Air Force Base for their financial support of this work and The Ohio State University Computer Center for the computer time which they contributed. VITA October 8, 1936 Born - Kansas City, Kansas 1959 ............. B.S. Metallurgical Engineering, University of Missouri - Rolla, Rolla, Missouri 1960 ............. M.S. Metallurgical Engineering, University of Missouri - Rolla, Rolla, Missouri 1960-1965.........Research Metallurgist; Nonferrous Metallurgy Division, Battelle Memorial Institute, Columbus, Ohio, and part-time graduate student at The Ohio State University 1965-1967.........Research Metallurgist; Bar, Plate, and Forged Products Division, United States Steel Applied Research Laboratory, Monroeville, Pennsyl­ vania, and part-time graduate student at the Carnegie-Mellon University 1967-1969.........Research Associate; Department of Metallurgical Engineering, The Ohio' State University, Columbus, Ohio FIELDS OF STUDY Major Field: Metallurgical Engineering Studies in Physical Metallurgy; Professors G. W. Powell, J. W. Spretnak, and P. G. Shewmon Studies in Corrosion; Professors M.E. Straumanis and M. G. Fontana Studies in Kinetics; Professors R. O. Sutherland and W. J. James TABLE OF CONTENTS Page ACKNOWLEDGMENTS........................................ iii VITA ............................................. iv LIST OF FIGURES ........................................ vii LIST OF TABLES ...................................... x Chapter I. INTRODUCTION . 1 II. LITERATURE SURVEY ......................... 3 A. The Importance and Principles of Metal-Matrix, Fiber-Reinforced Composite Materials.................. 3 B. Reaction Diffusion in Binary Systems . 12 Experimental Observations Phenomenological Theory C. Reaction Diffusion in Multicomponent Systems ....................... 24 Phenomenological Theory Phase Rule and Representation of Diffusion Paths Experimental Observations III. REACTION-DIFFUSION IN A BINARY METAL-NONMETAL SYSTEM ..................... 33 A. Problem Statement and Assumptions . 34 v CONTENTS (Contd.) Chapter Page B. Mathematical Formulation ............. 36 Case I: Metal Initially Saturated with Nonmetal Case II: Metal Initially Not Saturated with Nonmetal C. Results and Discussion............... 42 IV. REACTION-DIFFUSION IN THE SYSTEMS Ti/SiC AND Ti-6Al-4V/SiC ........................ 49 A. Experimental Procedure ............... 49 Materials Diffusion Couple Preparation Alloy Preparation X-Ray Analysis Metallography Electron-Microprobe Analyses B. Results and Discussion............... 61 Reaction-Diffusion Kinetics X-Ray Analyses Metallographic and Electron Microprobe Analyses Diffusion Paths in the Ti/SiC System Mechanism of the Ti/SiC Reaction V. SUMMARY 113 APPENDIXES . 117 REFERENCES. 130 FIGURES Figure Page 1. Aerospace Materials Technology Envelope .... 5 2. Schematic Stress-Strain Diagram for a Metal- Matrix, Fiber-Reinforced Composite Material . 6 3. Theoretical Variation of Composite Strength with Volume Fraction of High-Strength, Brittle Fibers .......................................... 9 4. Concentration-Penetration Diagrams for Reaction-Diffusion in a Binary System where Three Phases are Involved ........................19 5. Relationship between the Concentration- Penetration Diagram and the Phase Diagram for Reaction-Diffusion in a Metal-Nonmetal Binary System ..................................... 37 TiC 6. Arrhenius Plot Comparing the Values of D Obtained by Vansant and Phelps1*0 with the Values Calculated from Equation (54).............44 7. Non-Parabolic Growth of the Titanium Carbide Reaction Layer as Numerically Computed from Equation (54) .............................. 45 8. Experimentally Observed Non-Parabolic Growth of the y-Phase in Ni/Al Diffusion Couples . 47 9. Microstructures of Initial Materials.......... *.52 10. Schematic Diagram Illustrating the Molybdenum Bonding Vessel Assembly ........................ 53 11. Specimen Holder for Polishing the Mating Diffusion Couple Surfaces ............. ....55 12. Technique for Polishing the Mating Diffusion Couple Surfaces . ................. 56 vii FIGURES (Contd.) Figure Page 13. Furnace Facility for Accomplishing Diffusion A n n e a l s ........................ ................ -57 14. Reaction-Zone Growth Kinetics for the Ti/SiC Diffusion Couples ........... 65 15. Arrhenius Plots for the Stages I and II Reactions in the Ti/SiC System.................... 68 16. Reaction-Zone Growth Kinetics for the Ti-6Al-4V/SiC Diffusion Couples ......... 71 17. Arrhenius Plots for the Stages I and II Reactions in the Ti-6Al-4V/SiC System .......... 73 18. Reaction-Zone Microstructures for Ti/SiC Diffusion Couples (A) Couple 4, Reacted 2.5- Hours at 1200°C (B) Couple 10, Reacted 75- Hours at 1200 °C ................................... 77 19. Reaction-Zone Microstructure and Partially Dissolved Tungsten Marker in a Ti/SiC Diffusion Couple Reacted 4-Hours at 1200°C. 80 20. Electron Microprobe Analyses for Silicon and Titanium in the Reaction-Zone of Ti/SiC Diffusion Couple 1 0 ...............................81 21. Electron Microprobe Analyses for Silicon and Titanium in the Reaction-Zone of Ti/SiC Diffusion Couple 1 0 ...............................82 22. Reaction-Zone Microstructures for Ti/SiC Diffusion Couples (A) Couple 13, Reacted 4- Hours at 1100°C (B) Couple 22/ Reacted 72- Hours at 1000°C ................................... 84 23. Electron Microprobe Analyses for Silicon and Titanium in the Reaction-Zone of Ti/SiC Diffusion Couple 2 2 .............. 86 24. Electron Microprobe. Analyses for Silicon and Titanium in the Reaction-Zone of Ti/SiC Diffusion Couple 2 2 .............................. 87 v4.i1 FIGURES (Contd.) Figure Page 25. Reaction-Zone Microstructures for Ti/SiC Diffusion Couple 8 Reacted 12-Hours at 1200°C . 88 26. Electron Microprobe Analyses for Silicon and Titanium in the Reaction-Zone of Ti/SiC Diffusion Couple 8............ 90 27. Reaction-Zone Microstructures for Ti-6Al-4V/SiC Diffusion Couples (A) Couple 8A, Reacted 26.5- Hours at 1100°C (B) Couple 5A, Reacted 74-Hours at 1 2 0 0 ° C .......................................... 91 28. Electron Microprobe Analyses for Aluminum and Vanadium in the Reaction-Zone of Ti-6Al-4V/SiC Diffusion Couple 5 A ................................ 93 29. Electron Microprobe Analyses for Silicon and Titanium in the Reaction-Zone of Ti-6Al-4V/SiC Diffusion Couple 5 A ................................ 94 30. Ternary Isotherm Proposed by Brukl1*7 for the System Ti-Si-C at 1200°C............................ 97 0 31. Revised Ternary Isotherm for the System Ti-Si-C at 1 2 0 0 ° C .................................. 99 32. Microstructures of the Ti-SiC Alloys...............101 33. Alloy Compositions and Electron Microprobe Analyses of the Phases Present in the Ti-Si-C Alloys. ....................................... 103 34. Diffusion Paths for the Stages I and II Reactions in the Ti/SiC Diffusion Couples Prepared from Commercially-Pure Titanium and Reacted at 1 2 0 0 ° C ................................. 105 35. Diffusion Paths for the Stages I and II Reactions in the Ti/SiC Diffusion Couples Prepared from Commercially-Pure Titanium and Reacted at 1100° and 1 0 0 0 ° C ...................... 106 36. Diffusion Path for the Ti/SiC Diffusion Couples Prepared from Carbon Satruated Titanium and Reacted at 1200°C.................... 107 TABLES Table Page 1. Comp^r^son of Numerically Computed Values of D with the Values Obtained by Vansant and Phelps'*0 ........................................41 2. Chemical Analyses of the Materials for Diffusion Couples ..............................
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