Superalloys, Supercomposites and Superceramics

Superalloys, Supercomposites and Superceramics reviews the state of superalloy technology and some of the more salient aspects of alternative high temperature systems such as superceramics and supercomposites. Superalloy topics range from resource availability to advanced processing such as VIM, VAR, and VADAR, along with investment casting and single crystal growth, new superplastic forming techniques and powder metallurgy, structure property relationships, strengthening mechanisms, oxidation, hydrogen embrittlement, and phase predictions. This book is comprised of 22 chapters that explore key issues of high temperature materials in a synergistic manner. The first chapter reflects on the growth of the superalloy industry and its technology over the past 40 years. The discussion then turns to some of the trends in superalloy development, focusing on what is understood to be meant by the term strategic materials and the current status of resources and reserves in the United States. Particular attention is given to the supply sources and availability of strategic materials. The results achieved from the research program undertaken by NASA Lewis Research Center named Conservation Of Strategic Aerospace Materials (COSAM) are also presented. The chapters that follow explore alternative high temperature systems such as intermetallics, fiber reinforced superalloys, and the processing and high temperature properties of ceramics and carbon-carbon composites. This book will be a valuable resource for professionals and graduate students interested in learning about superalloys, supercomposites, and superceramics.

Contributors

Preface

Foreword

1. Introduction—Superalloys

I. Superalloys

II. Superalloy Applications

III. Superalloy History

References

2. Resources—Supply and Availability

I. Introduction

II. Strategic Materials

III. Reserves and Resources

IV. The Superalloys

V. COSAM Program Summary

VI. Concluding Remarks

References

3. Primary and Secondary Melt Processing—Superalloys

I. Introduction

II. Defects

III. Cleanliness Evaluation

IV. Melting Alternatives

V. Vacuum Induction Melting

VI. Vacuum Arc Remelting

VII. Electroslag Remelting

VIII. Electron Beam Cold Hearth Refining

IX. Plasma Cold Hearth Refining

X. Powder Metallurgy

XI. Fine-Grain Casting

XII. Melt Processing Summary

XIII. The Future

References

4. Metallurgy of Investment Cast Superalloy Components

I. History of Superalloy Investment Casting

II. Making the Superalloy Investment Casting Shell

III. Production and Melting of Superalloy Ingot for Investment Casting

IV. Investment Casting Superalloy Components

V. Control of Microstructure through Solidification

VI. Post-Cast Processing

VII. Nondestructive Inspection of Superalloy Castings

VIII. Future of Investment Cast Superalloy Components

Acknowledgments

References

5. Single Crystal Superalloys

I. Introduction

II. Directional Solidification Process

III. Microstructure

IV. Phase Stability

V. Heat Treatment

VI. Compositional Effects

VII. Mechanical Properties

VIII. Oxidation/Hot Corrosion Resistance

IX. Future Directions

References

6. Thermomechanical Processing of Superalloys

I. Introduction

II. Selection of the Optimum Manufacturing Practice

III. Control of the Selected Process

IV. Summary

References

7. Alloying Effects on Hot Deformation

I. Introduction

II. Deformation Resistance at High Strain Rate

III. Deformation Resistance at Slow Strain Rate

IV. Hot Workability

V. Summary

Acknowledgment

References

8. Powder Metallurgy and Oxide Dispersion Processing of Superalloys

I. Introduction

II. Powder Production and Characterization

III. Consolidation

IV. Defects and Cleanliness

V. Post-Consolidation Processing

VI. Concluding Remarks

Acknowledgments

References

9. Oxide Dispersion Strengthened Alloys

I. Introduction

II. Microstructure of ODS Alloys

III. Nanostructural and Microstructural Effects on Strength

IV. Microstructural Instabilities

V. Summary

Acknowledgments

References

10. Creep-Fatigue Interaction in Structural Alloys

I. Introduction

II. Creep-Fatigue Interaction

III. Mechanisms and Models

IV. Concluding Remarks

References

11. Creep and Stress Rupture—Long Term

I. Introduction

II. Data Sources

III. Evaluation of Creep-Rupture Data

IV. Strain-Time Behavior

V. Microstructural Stability and Ductility Consideration

VI. Conclusion

Acknowledgment

References

12. Cyclic Deformation, Fatigue and Fatigue Crack Propagation in Ni-Base Alloys

I. Introduction

II. Fundamentals of Deformation in Superalloys

III. Damage Accumulation

IV. Fatigue Crack Propagation in Ni-Base Alloys

V. Concluding Remarks

References

13. Life Prediction and Fatigue

I. Introduction

II. High Temperature Alloys Investigated

III. Development of Life Prediction Methods

IV. Characterization of Crack Propagation in Superalloys

V. Factors Influencing the Fatigue Strength of Superalloys

VI. Development of New Alloys

VII. Fatigue of Other Superalloys

VIII. Closing Remarks

References

14. High Temperature Corrosion

I. Introduction

II. Thermodynamics

III. Fundamentals of High Temperature Corrosion

IV. Corrosion by Mixed Oxidants

V. Hot Corrosion of Metals and Alloys

VI. Coatings

VII. Summary

References

Appendix A

15. Hydrogen Embrittlement—Rocket Engine Applications

I. Introduction

II. Tensile Properties

III. Creep Rupture

IV. Fatigue

V. Fracture Mechanics

VI. Summary

References

16. Modeling of Ternary Phase Equilibrium by the Cluster Variation Method

I. Introduction

II. Thermodynamic Model

III. Results for Ternary Alloys

IV. Discussion and Conclusions

Acknowledgments

References

17. Role of Refractory Elements in Strengthening of γ' and γ" Precipitation Hardened Nickel-Base Superalloys

I. Introduction

II. Planar Faults and Dislocation Configurations in the L12 Structure

III. Deformation of Ni3Al ("-phase)

IV. Deformation of /"Alloys

V. Future Perspective

References

18. Strength and Ductility of Intermetallic Compounds

I. Introduction

II. Structure of L12 Ordered Alloys

III. Planar Faults and Dislocation Dissociation

IV. Flow of L12 Materials

V. Intergranular Fracture and Alloy Design

VI. Summary

Acknowledgment

References

19. Fiber Reinforced Superalloys

I. Introduction

II. Fiber Development

III. Matrix-Alloy Development

IV. Composite Fabrication

V. Composite Properties

VI. Stress-Rupture Strength

VII. Creep Resistance

VIII. Fatigue

IX. Impact Strength

X. Oxidation and Corrosion

XI. Thermal Conductivity

XII. Composite Component Fabrication

XIII. Concluding Remarks

References

20. Structural Ceramics: Processing and Properties

I. Introduction

II. The Advanced Structural Ceramic Families and Their General Properties

III. The Effect of Service Environment on Properties

IV. Applications

V. The Future

References

21. Some Aspects of the High Temperature Performance of Ceramics and Ceramic Composites

I. Introduction

II. Creep Ductility

III. Creep Crack Growth

IV. High Temperature Flaws

V. Ceramic Composites

VI. Concluding Remarks

References

22. The Processing and Properties of Some C/C Systems

I. Introduction

II. Process Description

III. Properties of C/C Composites

IV. Improvement in Properties of 3-D C/C Composites

V. Conclusion

References

Index