Engineering Materials and Processes Gerd Lütjering James C. Williams Titanium ndedition WithFiguresandTables 123 Prof.Dr.GerdLütjering TechnicalUniversityHamburg-Harburg DepartmentofPhysicalMetallurgyandMaterialsTechnology Hamburg Germany Prof.Dr.JamesC.Williams TheOhioStateUniversity DepartmentofMaterialsScienceandEngineering Columbus,OH USA SeriesEditor: ProfessorBrainDerby,ProfessorofMaterialsSciencs ManchesterScienceCentre,GrosvenorStreet,Manchester,MHS,UK LibraryofCongressControlNumber: ISSN - ISBN ---- nded.SpringerBerlinHeidelbergNewYork ISBN ---- sted.SpringerBerlinHeidelbergNewYork Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialisconcerned, specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,broadcasting,reproductionon microfilmorinanyotherway,andstorageindatabanks.Duplicationofthispublicationorpartsthereofisper- mittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember,,initscurrentversion,and permissionforusemustalwaysbeobtainedfromSpringer.ViolationsareliableforprosecutionundertheGerman CopyrightLaw. SpringerisapartofSpringerScience+BusinessMedia springer.com ©Springer-VerlagBerlinHeidelberg, Theuseofgeneraldescriptivenames,registerednames,trademarks,etc.inthispublicationdoesnotimply,evenin theabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevantprotectivelawsandregulations andthereforefreeforgeneraluse. Typesetting:Digitaldatasuppliedbytheauthors Production:LE-TEXJelonek,Schmidt&VöcklerGbR,Leipzig Coverdesign:WMXDesignGmbH,Heidelberg Printedonacid-freepaper SPIN //YL– Preface to the Second Edition When the authors were asked to prepare a Second Edition of the book Titanium the first question was timing. It was agreed that the new edition should be ready for the 11th World Conference of Titanium (Ti-2007) in Kyoto. This is four years after the First Edition was presented at the Ti-2003 conference in Hamburg. Fur- ther, the authors decided to keep the structure and content of the First Edition completely unchanged with the exception of correcting a few obvious mistakes. The Preface to the First Edition decribes the motivation and intent of the book. These also remain unchanged for the Second Edition. All of the new subjects are covered in the Second Edition as short sections which are placed at the end of the appropriate chapters. These new sections bear the title “Recent Developments since the First Edition”. In this way, it should be easy for both readers of the First Edition and for new readers to find those subjects which emerged during the last four years. The new subjects included in the book are from the technological side (Chap. 3): “New Titanium Production Methods”, “Friction Stir Processing”, “Low Plas- ticity Burnishing”, “Focused Ion Beam Device Applications”, and “Neural Net- works for Structure/Property Correlations”. From the materials side the following topics are included: “Effect of Ni Impurities on Creep Strength” in Chap. 6, “Gamma LPT Blades” in Chap. 8, and “Biomedical Materials” in Chap. 10. There also are new sections on β alloys (Ti-6246, Ti-5553, and Beta 21S) in Chap. 7. The section on “Dwell Fatigue” was included in Chap. 6 (High Temperature Al- loys) because this effect is most pronounced in these alloys. In addition, it was thought that a section on “Market Dynamics” should be discussed in the book and it was placed in the introduction chapter (Chap. 1). Finally, including a section dealing with the unpleasant discoloration behavior of titanium sheets used for the exterior of buildings was thought to be worthwhile. This section is entitled “Ap- pearance Related Problems” and can be found in Chap. 10. The authors’ selection of new subjects for inclusion in the Second Edition does not infer that there are not other topics which should also have been included. However, the total number ultimately was limited by the page allowance of the publisher. We would like to thank the following people for contributing to this Second Edition by reading one or more of the new sections and making helpful comments: R. G. Broadwell, H. L. Fraser, M. J. Mills, A. L. Pilchak, S. R. Seagle, M. J. Weimer. Especially, we thank S. Neft for taking her time to read all new sections and making valuable suggestions for improvements. Mr. S. Knütel typed and formatted the text of this Second Edition and Mrs. L. Wang prepared all the figures. The final desktop publishing was done, as also for the First Edition, by Mr. F. Reinarts, an “outside” desktop publishing expert. We VI Preface to the Second Edition would like to thank all three of them. Without their capable assistance this book would not have been finished on time. Finally, we wish to thank our wives, Heide and Joanne, for their patience and support during the time we worked on this Second Edition. Preface to the First Edition The authors were motivated to prepare this book by the absence of any recent comprehensive book on titanium. The intent of this book is to provide a modern compendium that addresses both the phyical metallurgy as well as the applications of titanium. Until now the only book on this subject is that by Zwicker which was written in German and published almost 30 years ago. Chapter 1 is an introduction to the subject including some historical aspects of titanium. Chapter 2 is a sum- mary of the Fundamental Aspects of Titanium, Chapter 3 is a summary of the Technological Aspects of Titanium and Chapters 4 through 9 address the specifics of the various classes of titanium ranging from CP Titanium to Titanium Matrix Composites. Finally, Chapter 10 covers “special” properties and applications of titanium. Our intent has been to address the subject conceptually rather than provide quantities of data of the sort that would be found in a Handbook. It is our intent that this book is useful for materials scientists and engineers interested in using titanium and for students either as a sourcebook or as a textbook. We have at- tempted to include a representative set of references which provide additional detail for readers interested in specific aspects of titanium. Because of the rela- tively recent growth of the technological importance of titanium, there is a volu- minous literature on titanium. While our references span this literature it has proven impossible to mention every contribution. We thank the following people for reading one or more chapters and providing suggestions that led to improvements in both the clarity and the content: J. Albrecht, R. G. Baggerly, M. J. Blackburn, J. P. Blank, R. R. Boyer, J. A. Hall, D. Helm, M. C. Juhas, J. M. Larsen, H. A. Lipsitt, S. Lütjering, J. O. Peters, S. R. Seagle, R. A. Sprague. Mrs. Zimmermann typed and formatted the text of this book and Ms. Wang performed all painstaking work on the figures. Without their dedicated help this book could not have been finished. We would like to thank both of them for their outstanding support. Finally, we wish to thank our wives, Heide und Joanne, for both their patience and encouragement while we worked on this project. Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Purpose of the Book . . . . . . . . . . . . . . . . . . 1 1.2 History of Titanium . . . . . . . . . . . . . . . . . . 2 1.3 Emergence as Commercial Material . . . . . . . . . . . . 2 1.4 Titanium Industry Status . . . . . . . . . . . . . . . . 4 1.5 Traditional and Emerging Applications . . . . . . . . . . 8 1.6 Recent Developments since the First Edition – Market Dynamics . . . . . . . . . . . . . . . . . . . 12 2 Fundamental Aspects . . . . . . . . . . . . . . . . . . 15 2.1 Basic Properties . . . . . . . . . . . . . . . . . . . . 15 2.2 Crystal Structure . . . . . . . . . . . . . . . . . . . . 16 2.3 Elastic Properties . . . . . . . . . . . . . . . . . . . 16 2.4 Deformation Modes . . . . . . . . . . . . . . . . . . 19 2.4.1 Slip Modes . . . . . . . . . . . . . . . . . . . 19 2.4.2 Deformation Twinning . . . . . . . . . . . . . . . 22 2.5 Phase Diagrams . . . . . . . . . . . . . . . . . . . . 23 2.6 Phase Transformations . . . . . . . . . . . . . . . . . 29 2.6.1 Martensite Transformation . . . . . . . . . . . . . 29 2.6.2 Nucleation and Diffusional Growth . . . . . . . . . . 32 2.7 Alloy Classification . . . . . . . . . . . . . . . . . . 33 2.8 Basic Hardening Mechanisms . . . . . . . . . . . . . . 36 2.8.1 Hardening of the Alpha Phase . . . . . . . . . . . . 37 2.8.2 Hardening of the Beta Phase . . . . . . . . . . . . . 38 2.9 Basic Physical and Chemical Properties . . . . . . . . . . 42 2.9.1 Diffusion . . . . . . . . . . . . . . . . . . . . 45 2.9.2 Corrosion Behavior . . . . . . . . . . . . . . . . 47 2.9.3 Oxidation . . . . . . . . . . . . . . . . . . . . 50 3 Technological Aspects . . . . . . . . . . . . . . . . . . 53 3.1 Sponge Production . . . . . . . . . . . . . . . . . . . 53 3.2 Melting . . . . . . . . . . . . . . . . . . . . . . . 59 3.2.1 Vacuum Arc Remelting (VAR) . . . . . . . . . . . . 60 3.2.2 Cold Hearth Melting (CHM) . . . . . . . . . . . . . 64 3.2.3 Melt Related Defects . . . . . . . . . . . . . . . . 68 X Contents 3.3 Primary Processing . . . . . . . . . . . . . . . . . . . 72 3.4 Shaping into Components . . . . . . . . . . . . . . . . 79 3.4.1 Forging . . . . . . . . . . . . . . . . . . . . . 79 3.4.2 Ring Rolling . . . . . . . . . . . . . . . . . . . 83 3.4.3 Metal Removal (Machining) . . . . . . . . . . . . . 85 3.5 Near Net Shape Processes . . . . . . . . . . . . . . . . 86 3.5.1 Casting . . . . . . . . . . . . . . . . . . . . . 87 3.5.2 Powder Metallurgy . . . . . . . . . . . . . . . . 91 3.5.3 Laser Forming . . . . . .. . . . . . . . . . . . . 95 3.5.4 Conventional Sheet Forming . . . . . . . . . . . . 97 3.5.5 Superplastic Forming and Diffusion Bonding . . . . . . 99 3.6 Conventional Joining Methods . . . . . . . . . . . . . . 104 3.6.1 Fusion Welding . . . . . . . . . . . . . . . . . . 104 3.6.2 Friction Welding . . . . . . . . . . . . . . . . . 111 3.7 Surface Treatment . . . . . . . . . . . . . . . . . . . 115 3.7.1 Shot Peening . . . . . . . . . . . . . . . . . . . 116 3.7.2 Laser Shock Processing . . . . . . . . . . . . . . . 120 3.7.3 Chemical Milling . . . . . . . . . . . . . . . . . 123 3.7.4 Electrochemical Machining . . . . . . . . . . . . . 125 3.8 Inspection Methods . . . . . . . . . . . . . . . . . . . 125 3.8.1 Ultrasonic Inspection . . . . . . . . . . . . . . . . 126 3.8.2 Radiographic Inspection . . . . . . . . . . . . . . 131 3.8.3 Surface Etching Inspection . . . . . . . . . . . . . 131 3.8.4 Eddy Current Inspection . . . . . . . . . . . . . . 134 3.8.5 Dye Penetrant Inspection . . . . . . . . . . . . . . 135 3.8.6 Surface Replication . . . . . . . . . . . . . . . . 136 3.9 Characterization Methods . . . . . . . . . . . . . . . . 136 3.9.1 Light Microscopy . . . . . . . . . . . . . . . . . 137 3.9.2 Electron Microscopy . . . . . . . . . . . . . . . . 141 3.9.2.1 Transmission Electron Microscopy . . . . . . . 141 3.9.2.2 Scanning Electron Microscopy . . . . . . . . . 145 3.9.3 X-ray Diffraction . . . . . . . . . . . . . . . . . 148 3.9.4 Mechanical Testing . . . . . . . . . . . . . . . . 149 3.10 Recent Developments since the First Edition . . . . . . . . 150 3.10.1 New Titanium Production Methods . . . . . . . . . . 150 3.10.2 Friction Stir Processing . . . . . . . . . . . . . . 153 3.10.3 Low Plasticity Burnishing . . . . . . . . . . . . . 157 3.10.4 Focused Ion Beam Device Applications . . . . . . . . 161 3.10.5 Neural Networks for Structure/Property Correlations . . . 167 4 Commercially Pure (CP) Titanium and Alpha Alloys . . . . . 175 4.1 Processing and Microstructure . . . . . . . . . . . . . . 177 4.1.1 Material Processing . . . . . . . . . . . . . . . . 177 4.1.2 Processing into Components . . . . . . . . . . . . . 183 4.2 Microstructure, Composition, and Properties . . . . . . . . . 185 Contents XI 4.3 Properties and Applications . . . . . . . . . . . . . . . 198 5. Alpha + Beta Alloys . . . . . . . . . . . . . . . . . . . 203 5.1 Processing and Microstructure . . . . . . . . . . . . . . 203 5.1.1 Fully Lamellar Microstructures . . . . . . . . . . . . 203 5.1.2 Bi-Modal Microstructures . . . . . . . . . . . . . . 208 5.1.3 Fully Equiaxed Microstructures . . . . . . . . . . . 212 5.2 Microstructure and Mechanical Properties . . . . . . . . . . 216 5.2.1 Fully Lamellar Microstructures . . . . . . . . . . . . 218 5.2.2 Bi-Modal Microstructures . . . . . . . . . . . . . . 227 5.2.3 Fully Equiaxed Microstructures . . . . . . . . . . . 234 5.2.4 Effect of Aging and Oxygen Content . . . . . . . . . 238 5.2.5 Effect of Secondary Alpha in Beta Phase . . . . . . . . 243 5.2.6 Effect of Crystallographic Texture . . . . . . . . . . 246 5.3 Properties and Applications . . . . . . . . . . . . . . . 250 6 High Temperature Alloys . . . . . . . . . . . . . . . . . 259 6.1 Processing and Microstructure . . . . . . . . . . . . . . 260 6.2 Microstructure and Mechanical Properties . . . . . . . . . . 261 6.3 Properties and Applications . . . . . . . . . . . . . . . 270 6.4 Recent Developments since the First Edition . . . . . . . . . 272 6.4.1 Dwell Fatigue . . . . . . . . . . . . . . . . . . 272 6.4.2 Effect of Ni Impurities on Creep Strength . . . . . . . . 279 7 Beta Alloys . . . . . . . . . . . . . . . . . . . . . . . 283 7.1 Processing and Microstructure . . . . . . . . . . . . . . 283 7.1.1 Beta Annealed Microstructures . . . . . . . . . . . . 284 7.1.2 Beta Processed Microstructures . . . . . . . . . . . . 290 7.1.3 Through-Transus Processed Microstructures . . . . . . 292 7.1.4 Bi-Modal Microstructures . . . . . . . . . . . . . . 295 7.2 Microstructure and Mechanical Properties . . . . . . . . . . 297 7.2.1 Effect of Processing Route . . . . . . . . . . . . . 299 7.2.1.1 Tensile Properties . . . . . . . . . . . . . . 299 7.2.1.2 Fatigue Properties . . . . . . . . . . . . . . 302 7.2.1.3 Fracture Toughness . . . . . . . . . . . . . 308 7.2.2 Effect of Age-Hardening . . . . . . . . . . . . . . 310 7.2.3 Effect of Beta Grain Size . . . . . . . . . . . . . . 315 7.3 Properties and Applications . . . . . . . . . . . . . . . . 317 7.4 Recent Developments since the First Edition . . . . . . . . . 323 7.4.1 Effect of Yield Stress Level on Properties of Ti-6246 . . . 323 7.4.2 Optimization of Properties of Ti-5553 . . . . . . . . . 330 7.4.3 Distribution of Alpha Precipitates in Beta 21S . . . . . . 332 XII Contents 8 Titanium Based Intermetallics . . . . . . . . . . . . . . 337 8.1 Alloying and Microstructure . . . . . . . . . . . . . . . 338 8.2 Microstructure and Properties . . . . . . . . . . . . . . 348 8.2.1 Alpha 2 and Orthorhombic Alloys . . . . . . . . . . 349 8.2.2 Gamma Alloys . . . . . . . . . . . . . . . . . . 354 8.3 Applications . . . . . . . . . . . . . . . . . . . . 356 8.4. Recent Developments since the First Edition − Gamma LPT Blades. . . . . . . . . . . . . . . . . . . 360 9 Titanium Matrix Composites . . . . . . . . . . . . . . . 367 9.1 Processing . . . . . . . . . . . . . . . . . . . . . . 367 9.2 Properties . . . . . . . . . . . . . . . . . . . . . . 372 9.2.1 Tensile Properties . . . . . . . . . . . . . . . . . 372 9.2.2 Fatigue Properties . . . . . . . . . . . . . . . . . 375 9.2.3 Creep Properties . . . . . . . . . . . . . . . . . . 377 9.3 Applications . . . . . . . . . . . . . . . . . . . . . 379 10 Special Properties and Applications of Titanium . . . . . . 383 10.1 Superconductivity . . . . . . . . . . . . . . . . . . . 383 10.2 Burn Resistance . . . . . . . . . . . . . . . . . . . . 388 10.2.1 Phenomenology of Titanium Fires . . . . . . . . . . 389 10.2.2 Alloy Selection for Fire Risk Mitigation . . . . . . . 390 10.3 Hydrogen Storage . . . . . . . . . . . . . . . . . . . 391 10.4 Shape Memory Effect . . . . . . . . . . . . . . . . . . 393 10.4.1 Phenomenology of the Shape Memory Effect . . . . . 393 10.4.2 Applications of Shape Memory Alloys . . . . . . . . 397 10.5 Biomedical Applications . . . . . . . . . . . . . . . . 399 10.6 Automotive Applications . . . . . . . . . . . . . . . . 403 10.7 Sports Related Applications . . . . . . . . . . . . . . . 406 10.8 Appearance Related Applications . . . . . . . . . . . . . 408 10.9 Recent Developments since the First Edition . . . . . . . . . 410 10.9.1 Biomedical Materials . . . . . . . . . . . . . . . 410 10.9.2 Appearance Related Problems . . . . . . . . . . . . 413 References . . . . . . . . . . . . . . . . . . . . . . . . . 417 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . 431