Aerospace Alloys (eBook)

Preface 7
Contents 9
Abbreviations 13
About the Author 18
Chapter 1: A Brief Introduction to Aerospace Applications 19
1.1 Historical Background 19
1.2 Novel Design Criteria 26
1.3 Aerospace-Related Fields 32
References 33
Further Reading 34
Chapter 2: Gas Turbine Aero-Engines 35
2.1 Introduction 35
2.2 Types of Aircraft Engines 36
2.3 Compressors 44
2.4 Combustors 46
2.5 Turbines 49
2.6 State of the Art and Future Trends 51
References 56
Further Reading 57
Chapter 3: Alloys for Aircraft Structures 58
3.1 Introduction 58
3.2 Aluminum Alloys 59
3.2.1 Introduction 59
3.2.2 Cast Alloys 68
3.2.3 Wrought Alloys 70
3.2.3.1 Wrought Non-heat Treatable Alloys 75
3.2.3.2 Heat-Treatable Alloys and Designation of Tempers 77
3.2.3.3 Precipitation Hardening 79
3.2.4 Aluminum-Lithium Alloys 90
3.2.5 Aluminum Alloys in Aircraft Structures: Present State and Perspectives 94
3.3 Magnesium Alloys 104
3.3.1 Introduction 104
3.3.2 Aerospace Magnesium Alloys: Metallurgy, Main Designation System, and Tempers 112
3.3.3 Magnesium Alloy Processing 115
3.3.4 Development of Aerospace Magnesium Alloys 116
3.3.5 Current Aerospace Applications 123
3.4 Composite Materials 127
3.4.1 Introduction 127
3.4.2 Fiber-Metal Laminates: Development and Designation 129
3.4.3 Main Production Steps and Resulting Characteristics 130
3.4.4 Mechanical Properties 135
3.4.5 Applications 139
References 141
Further Reading 144
Chapter 4: Titanium and Titanium Alloys 145
4.1 Introduction 145
4.2 Physical Metallurgy Aspects 152
4.3 Main Groups of the Titanium Alloys 161
4.3.1 Conventional Titanium Alloys 162
4.3.1.1 ?-Alloys 162
4.3.1.2 ? + ? Alloys 166
4.3.1.3 Near-? Alloys 167
4.3.1.4 ?-Alloys 169
4.3.1.5 Thermal Treatments and Properties of Conventional Titanium Alloys 172
4.3.2 Advanced Titanium Alloys 180
4.4 Titanium Processing Technologies 185
4.5 Defects in Titanium Alloys and Diagnostics 195
4.6 Main Aerospace Applications of Titanium Alloys 198
References 203
Further Reading 205
Chapter 5: Steels 206
5.1 Introduction 206
5.2 Iron and Steel Metallurgical Base Concepts 208
5.2.1 Annealing 208
5.2.2 Quenching 209
5.2.3 Tempering 212
5.2.4 Age Hardening 214
5.2.5 Steel Designation 214
5.3 Standard and Special Production Techniques 215
5.3.1 Arc Melting 216
5.3.2 Vacuum Induction Melting (VIM) 218
5.3.3 Argon Oxygen Decarburization (AOD) 218
5.3.4 Vacuum Oxygen Decarburization (VOD and VODC) 222
5.3.5 Electroslag Remelting (ESR) 224
5.3.6 Vacuum Arc Remelting (VAR) 227
5.4 Steels for Aerospace Applications 231
5.4.1 Maraging Steels 231
5.4.2 AerMet Steels 241
5.4.3 Stainless Steels 245
5.4.3.1 Austenitic Stainless Steels 246
5.4.3.2 Martensitic Stainless Steels 252
5.4.3.3 PH Stainless Steels 260
5.5 Steel-Based Aerospace Components 267
5.5.1 Bearings 268
5.5.2 Brake Systems 269
5.5.3 Gas Turbine Jet Engine Parts 273
5.5.4 Gearboxes 273
5.5.5 Undercarriage Applications 275
5.5.6 Wings and Engine Pylons 275
5.5.7 Aerospace Applications of Steels: An Overview 276
References 279
Further Reading 281
Chapter 6: Superalloys 282
6.1 Introduction 282
6.2 Cobalt-Based Superalloys 289
6.2.1 Main Constituent Elements and Relevant Strengthening Mechanisms 297
6.2.2 Latest Developments of Co Superalloys 301
6.3 Iron-Based Superalloys 304
6.3.1 Strengthening Mechanisms and Classification of Iron-Based Superalloys 305
6.3.2 Alloy 718 and Properties of Iron-Based Superalloys 312
6.4 Nickel-Based Superalloys 314
6.4.1 Relevant Metallurgical Issues 326
6.4.1.1 Solid Phase Interfaces 329
6.4.1.2 Dislocations Structure and Dynamics in Ordered Alloys 333
6.4.2 Selection Criteria for Alloying Elements in Nickel-Based Superalloys: The ? Matrix 336
6.4.3 Selection Criteria for Alloying Elements in Nickel-Based Superalloys: The ?? Precipitates 346
6.5 Single-Crystal and Directionally Solidified Superalloys 358
6.5.1 Properties of DS and SC Superalloys 360
6.5.2 Principles and Technological Aspects of Directional Solidification 369
6.6 Heat Treatments 379
6.7 Applications of Superalloys in the Aerospace Field 393
References 398
Further Reading 401
Chapter 7: Coatings 402
7.1 General Aspects 402
7.2 Coating Deposition Techniques for Gas Turbine Engines 403
7.2.1 Thermal Spraying 405
7.2.1.1 Flame Spraying 406
7.2.1.2 High-Velocity Oxy-fuel Flame Spraying 407
7.2.1.3 Detonation Gun (D-Gun) and the Derived Super-Detonation Gun (Super D-Gun) 407
7.2.1.4 Electric Arc Spraying 408
7.2.1.5 Plasma Spraying 409
7.2.2 Physical Vapor Deposition 411
7.2.3 Chemical Vapor Deposition 413
7.3 Main Coating Systems in Gas Turbine Engines 416
7.3.1 Coatings Resistant to High-Temperature Corrosion 417
7.3.2 Thermal Barrier Coatings 424
7.3.3 Failure Mechanisms of Corrosion Resistant and Thermal Barrier Coatings 434
7.3.4 Clearance Coatings 439
7.3.5 Erosion- and Fretting-Resistant Coatings 443
References 446
Further Reading 453
Chapter 8: Corrosion 454
8.1 Introduction 454
8.1.1 General Corrosion 459
8.1.2 Pitting Corrosion 460
8.1.3 Crevice Corrosion 463
8.1.4 Selective Corrosion 464
8.1.5 Galvanic Corrosion (Two-Metal Corrosion) 466
8.1.6 Mechanochemical Corrosion 466
8.1.7 Hydrogen Embrittlement 471
8.2 High-Temperature Corrosion 474
8.2.1 High-Temperature Oxidation: General Thermodynamic and Kinetic Aspects 474
8.2.2 Alloy Oxidation 482
8.2.3 Surface Nanocrystallization 487
8.2.4 Gas Phase Corrosion: Sulfur-Induced Corrosive Processes 493
8.2.5 Hot Corrosion 495
8.2.6 Hot Corrosion Testing 507
References 511
Further Reading 514
Chapter 9: Other Interesting Alloys for Aerospace and Related Applications 515
9.1 Introduction 515
9.2 Refractory Alloys 516
9.2.1 General Aspects 516
9.2.2 Refractory Metal Alloys 518
9.2.3 Other Refractory Alloys: Chromium and the Platinum Group Metals 523
9.3 ODS: Oxide Dispersion Strengthened Alloys 525
9.4 Intermetallic Compounds and Ordered Alloys 534
9.5 Shape Memory Alloys 540
9.5.1 Main Phenomenological Aspects and Relevant Mechanisms 540
9.5.2 Aerospace Applications of Shape Memory Alloys 545
References 551
Further Reading 559
Appendices 560
Appendix 1: Wrought Aluminum Alloys and Relevant Compositions 560
Appendix 2: Alloying Elements in Cast and Wrought Aluminum Alloys 563
Appendix 3: Alloying Elements in Magnesium Alloys 565
Appendix 4: Alloying Elements in Steels 567
Appendix 5: Alloying Elements in Superalloys 576
Appendix 6: Precipitates and Secondary Phases in Superalloys 579