Article Sidebar

Submitted
July 30, 2023
Published
July 30, 2023
Download
PDF
Statistic
Read Counter : 206 Download : 94

Downloads

Download data is not yet available.

Metrics

Metrics Loading ...

Main Article Content

Abstract

The modern turbo-engine is one of the finest examples of engineering ingenuity, complexity and usefulness. The turbo-engine, whether used in land-based power generating equipment or in aircraft propulsion, has had a profound impact on our lives. Increasing air-travel, rising fuel prices, and environmental concerns have all combined to increase the need for more fuel-efficient engines. The blades of the high-pressure turbine are the most severely loaded members in the turbo-engine. The various aspects of these blades are described. First, the major components of a turbo-engine as well as the different types of turbo-engines are briefly described. Then the development of the turbo-engine is placed in its historical perspective. Next, the severity of the blade loading conditions, such as high temperatures, high centrifugal stresses, corrosion, oxidation, sulphidation, foreign object damage, etc., and the resulting failure modes are summarized. Super alloys are the materials of choice for these blades. The incremental improvements in the alloy chemistry are briefly traced. Important developments in the blade manufacture, the different types of blade cooling channels and their machining, thermal barrier coatings to decrease the blade temperature while increasing the Turbine Inlet Temperature (TIT), and future trends are discussed. The future belongs inevitably to advanced ceramics and their composites, with coatings for environmental protection.

Article Details

How to Cite
Prabhakaran, R. (2023). The High Pressure Gas Turbine Blades of Jet Engines. Journal of Aerospace Sciences and Technologies, 69(2), 261–285. https://doi.org/10.61653/joast.v69i2.2019.200
Download Citation
Endnote/Zotero/Mendeley (RIS)
BibTeX

References

  1. Ahmad F. El-Sayed., "Aircraft Propulsion and Gas Turbine Engines", CRC Press, 2008, ISBN-13: 9780849391965.
  2. Klaus Hunecke., Jet Engines: Fundamentals of Theory, Design and Operation", The Crowood Press, UK, ISBN: 0-7603-0459-9.
  3. Airplane Flying Handbook, FAA-H-8083-3A, US Department of Transportation, Federal Aviation Administration, 2004.
  4. Owen, J. M., "Developments in Aero Engines", Pertanika Journal of Science and Technology 9(2), 2001, pp.127-138.
  5. Torenbee, K. E. and Wittenberg, H., "Flight Physics: Essentials of Aeronautical Disciplines and Technology with Historical Notes", Springer, 2009, ISBN 978-1-4020-8663-2.
  6. Golley, J. and Gunston, B., "Genesis of the Jet-Frank Whittle and the Invention of the Jet Engine", Airlife Publishing, Shrewsbury, 1996, ISBN 185310 860 x.
  7. Glyn, J., "The Jet Pioneers-The Birth of the Jet-Powered Flight", Methuen, London, 1989, ISBN 0413 50400 x.
  8. Gibbs-Smith, C. H., "Aviation: An Historical Survey from its Origins to the End of World War II", London: HMSO, 1970.
  9. "Early Gas Turbine History", MIT Gas Turbine Laboratory, http://web.mit.edu/aeroastro/labs/gtl/ early_GT_history.html
  10. Koff, B. L., "Gas Turbine Technology Evolution-A Designers Perspective", AIAA/ICAS International Air and Space Symposium and Exposition: The Next 100 Y, 14-17 July 20003, Dayton, OH, AIAA 2003.
  11. Meher-Homji, C. B., "The Development of the Whittle Turbojet", J. Eng. Gas Turbines and Power, Vol.120, 1998, pp.249-256.
  12. Cervenka, M., "The Rolls Royce Trent Engine", 5 October 2000.
  13. Zaretsky, E. V., Litt, J. S., Hendricks, R. C., and Soditus, S. M., "Determination of Turbine Blade Life from Engine Field Data", Journal of Propulsion and Power, Vol.28, No.6, November-December 2012, pp.1156-1167.
  14. Rao, V. N. B., Kumar, I. N. N., Madhulata, N. and Abhijeet, A., "Mechanical Analysis of First Stage Marine Gas Turbine Blade", Int. Journal of Advanced Science and Technology, Vol.68, 2014, pp.57-64.
  15. "Jet Engine Design: The Turbine", Aerodynamics, Manufacturing, Technology, April 6, 2013.
  16. Homji, C. B. M. and Gabriles, G., "Gas Turbine Blade Failures- Causes, Avoidance, and Troubleshooting", Proceedings of the 27th Turbomachinery Symposium, Turbomachinery Laboratories, Texas A & M University, Houston, Texas, September 22-24, 1998.
  17. Bhagi, L. K., Rastogi, V. and Gupta, P., "A Brief Review on Failure of Turbine Blades", Proceedings of STME-2013, Smart Technologies for Mechanical Engineering, 25-26 October 2013 at Delhi Technological University, Delhi, India.
  18. Hou, J., Wicks, B. J. and Antoniou, R. A., "An Investigation of Fatigue Failures of Turbine Blades in a Gas Turbine Engine by Mechanical Analysis", Engineering Failure Analysis, Vol.9, 2002, pp.201- 211.
  19. Mazur, Z., Rez, L. R. Islas, J. A. J. and Amezcua, A. C., "Failure Analysis of a Gas Turbine Blade Made of Inconel 738 LC Alloy", Engineering Failure Analysis, Vol.12, 2005, pp.474-486.
  20. Naeem, M. T., Jazayeri, S. A. and Rezamahdi, N., "Failure Analysis of Gas Turbine Blades", Proceedings, IAJC-IJME International Conference Paper 120, 208, ENG 108.
  21. Tang, H., Cao, D., Yao, H., Xie, M. and Duan, R., "Fretting Fatigue Failure of an Aero Engine Turbine Blade", Engineering Failure Analysis, Vol.16, 2009, pp.2004-2008.
  22. Rajasekaran, R. and Nowell, D., "Fretting Fatigue in Dovetail Blade Roots: Experiment and Analysis", Journal of Tribology International, Vol.39, 2006, pp.1277-1285.
  23. Ebara, R., "Corrosion Fatigue Phenomena Learned from Failure Analysis", Engineering Failure Analysis, Vol.13, 2006, pp.516-525.
  24. Boyer, H., E., Editor, "Failure Analysis and Prevention", Metals Handbook, Eighth Edition, 1975, ASM.
  25. De Crescente, M. A., "Sulphidation and its Inhibition in Turbomachinery", Proceedings of the Ninth Turbomachinery Symposium, Turbomachinery Laboratory, Texas A&M University, College Station, Texas, 1980, pp.63-68.
  26. Stringer, J., "High Temperature Corrosion of Aerospace Alloys", AGARDograph No. 200, NATO Advisory Group for Aerospace Research and Development, Neuilly-sur-Seine, 1975.
  27. Bornstein, N., S., "Reviewing Sulphidation Corrosion- Yesterday and Today", JOM, Vol.48, Issue 11, November 1996, pp.37-39.
  28. Allen, W. A., and Bornstein, N. S., "Sulphidation Corrosion Revisited", Proceedings of the Fourth International Symposium on High Temperature Corrosion, New York, Elsevier Science Publishers, 1996.
  29. Santoro, G. S. et al., "Deposition on Na2SO4 from Salt Seeded Combustion Gases of a High Velocity Burner Rig", High Temperature Corrosion of Energy Systems, Edited by Michael Rothman, Warrendale, Pennsylvania, TMS, 1985.
  30. Tanzer, A., "Determination and Classification of Damage", Failure Analysis and Prevention, Vol.11, ASM Handbook, ASM International, 2002, pp.343- 350.
  31. Benac, D. J. and Swaminathan, V. P., "Elevated Temperature Life Assessment for Turbine Components, Piping and Tubing", Failure Analysis and Prevention, Vol.11, ASM Handbook, ASM International, 2002, pp.289-311.
  32. Jayakumar, T., Muralidharan, N, G., Raghu, N., Kasiviswanathan, K. V. and Raj, B., "Failure analysis Towards Reliability Performance of Aero Engines", Defence Science Journal, Vol.49, No.4, 1999, pp.311-316.
  33. Conner, M., "Hans von Ohain: Elegance in Flight", AIAA, 2001, ISBN: 1-56347-520-0.
  34. Schafrik, R., "Materials in Jet Engines: Past, Present and Future", General Manager, Materials and Process Engineering, GE Aircraft Engines, Power Point Presentation.
  35. Nathan, S., "Jewel in the Crown: Rolls Royces Single Crystal Turbine Blade Casting Foundry", 8th June 2015, https://www.theengineer.co.uk/jewel-in-thecrown- rolls-royces-single-crystal-turbine-blade.
  36. Knight, L., "The Metal that brought you Cheap Flights", Magazine, 16th May 2015, http://www.bbc. com/news/magazine-32749262.
  37. Cervenka, M., "The Rolls Royce Trent Engine", Rolls Royce, 5th October, 2000, Power Point Presentation.
  38. Cahn, R. W., The Coming of Material Science, March 2001, Pergamon, ISBN: 9780080426792.
  39. Taylor, A. and Floyd, R. W., "The Constitution of Nickel-Rich Alloys of the Nickel-Chromium-Aluminum System", Journal of the Institute of Metals, Vol.81, 1952-53, pp.451-464.
  40. Westbrook, J. H., "Temperature Dependence of the Hardness of Secondary Phases Common in Turbine Bucket Alloys", Trans. AIME, 1957, pp.898-904.
  41. Estrada, ., A. M., "New Technology used in Gas Turbine Blade Materials", Scientia et Technica Ano XIII, No.36, September 2007, Universidad Tecnologica de Pereira, ISSN 0122-1701, pp.297-301.
  42. Kawagishi, K., Harada, H., Sato, A. and Kobayashi, T., "The Oxidation Properties of Fourth Generation Single Crystal Based Super Alloys", JOM, January 2006, pp.43-46.
  43. Kawagishi, K., Yeh, A. C., Yokokawa, T., Kobayashi, T., Koizumi, Y. and Harada, H., "Development of an Oxidation Resistant High Strength Sixth Generation Single Crystal Super Alloy TMS-238", Super Alloys 2012, 12th International Symposium on Super Alloys, TMS (The Minerals, Metals & Materials) Society, 2012, pp.189-195.
  44. Sato, A., Yeh, A. C., Kobayashi, T., Yokokawa, T., Harada, H., Murakuma, T. and Zhang, J. X., "Fifth Generation Nickel Based Single crystal Super Alloy with Superior Elevated Temperature Properties", Energy Materials, Vo.2, No.1, 2007, pp.19-25.
  45. Caron, P. and Khan, T., ""Evolution of Nickel Based Super Alloys for Single Crystal Gas Turbine Blade Applications", Aerospace Science and Technology, Vol.3, 1999, pp.513-523.
  46. Haselbach, F. and Parker, R., "Hot End Technology for Advanced Low Emission Large Civil Aircraft Engines", 28th International Congress of the Aeronautical Sciences (ICAS), 2012, pp.1-12.
  47. Caron, P. and Lavigne, O., "Recent Studies at ONERA on Super Alloys for Single Crystal Turbine Blades", Journal Aerospace Lab, Issue 3, November 2011, AL03-02, pp.1-14.
  48. Reed, R. C., Huron, E. S., Hardy, M. C., Mills, M. J., Mantero, R. E., Portello, P. D. and Telesman, J., "Super Alloys", 2012, Wiley, ISBN: 1118516400.
  49. Donachie, M. J. and Donachi, S. J., "Super Alloys: A Technical Guide", 2nd Edition, ASM International, 2002, ISBN 1615030646.
  50. Watson, J. E., "Super Alloys: Production, Properties and Applications", Nova Science Publishers, 2011, ISBN 9781612095363.
  51. Bowman, R., "Super Alloys: A Primer and History", Supplement to the Minerals, Metals and Materials Society’s 9th International Symposium on Super Alloys, http://www.tms.org/meetings/specialty/superalloys 2000/superalloyhistory.html.
  52. Zhang, H., Xu, Q. and Liu, B., "Numerical Simulation and Optimization of Directional Solidification Process of Single Crystal Superalloy Casting", Materials, Vol.7, No.3, 2014, pp.1625-1639.
  53. Gell, M., Duhl, D. and Giamei, A., "The Development of Single Crystal Super Alloy Turbine Blades", Super Alloys, 1980, Proceedings of the Fourth International Symposium on Super Alloys, American Society of Metals, Metals Park, OH, 1980, pp.205-214.
  54. Segersall, M., "Nickel-Based Single Crystal Super Alloys: The Crystal Orientation Influence on High Temperature Properties", Linkoping University Institute of Technology, Licentiate Thesis No.1568, March 2013.
  55. Onyszko, A., Kubiak, K. and Sieniawski, J., "Turbine Blades of the Single Crystal Nickel Based CMSX-6 Super Alloy", Journal of Achievements in Materials and Manufacturing Engineering, Vol.32, Issue 1, January 2009, pp.66-69.
  56. Zhang, R. L., Chen, L. N., Li, C. H., Wang, N., Lu, X. G. and Ren, Z. M., "Influence of Spiral Crystal Selector on Crystal Orientation of Single Crystal Super Alloy", Transactions of Nonferrous Metals Society of China, Vol.22, 2012, pp.1092-1095.
  57. Esaka, H., Shinozuka, K. and Tamura, M., "Analysis of Single Crystal Casting Process Taking into Account the Shape of Pigtail", Journal of Materials Science and Engineering A, 2005, pp.413-414.
  58. "Strengthened Super Alloy for Gas Turbine Blades", Metal Powder Report, Vol.47, Issue 10, October 1992, pp.24-28.
  59. Suryanarayana, C., "Mechanical Alloying and Milling", Marcel Dekker, CRC Press, Taylor and Francis Group, 2004, ISBN 13:978-0-203-02064-7.
  60. Park, L. J., Ryu, H. J., Hong, S. H. and Kim, Y. G., "Microstructure and Mechanical Behavior of Me- chanically Alloyed ODS Ni-Base Super Alloy for Aerospace Gas Turbine Application", Advanced Performance Materials, Vol.5, 1998, pp.279-290.
  61. Gell, M. and Thomas, K. M., "Development and Design of Directionally Solidified Eutectic Airfoils for Advanced Gas Turbine Engines", The American Society of Mechanical Engineers, Paper No. 76-GT- 32, The Gas Turbine and Fluids Engineering Conference, New Orleans, La., March 21-25, 1976.
  62. Dunlevey, F. M. and Wallace, J. F., "The Effect of Thermal Cycling on the Structure and Properties of a Co, Cr, Ni-TaC Directionally Solidified Eutectic Alloy", Transformations, Metallurgical Transactions, Vol.5, Issue 6, June 1974, pp.1351-1356.
  63. Schilke, P. W., "Advanced Gas Turbine Materials and Coatings", GE Energy, GER-35696 (08/04).
  64. Clemens, M. L., Price, A. and Bellows, R. S., "Advanced Solidification 31. Processing of an Industrial Gas Turbine Engine Component", JOM, March 2003, pp.27- 31.
  65. Power, D. C., "Palladium Alloy Pinning Wires for Gas Turbine Blade Investment Casting", Platinum Metals Rev., Vol.39 (3), 1995, pp.117-126.
  66. Visual Manufacturing Help: Investment Casting http://www.custompartnet.com/wu/investment_cas ting
  67. Chyu, M. K. and Siw, S. C., "Recent Advances of Internal Cooling Techniques for Gas Turbine Airfoils", Journal of Thermal Science and Engineering Applications, Vol.5, June 2013, pp.021008-1 to 021008-12.
  68. Siddique, W., "Design of Internal Cooling Passages: Investigation of Thermal Performance of Serpentine Passages", Doctoral Thesis, 2011, Division of Heat and Power Technology, Royal Institute of Technology, Stockholm, Sweden, Report 11/09, ISBN 978- 91-7501-147-9.
  69. "Turbine Blade Cooling", Ecole Polytechnique Federale de Lausanne, http://gtt.epfl.ch/page-63563- fr.html.
  70. Al-Hadhrami, L. M, Shaahid, S. M, and Al-Mubarak, A. A., "Jet Impingement Cooling in Gas Turbines for Improving Thermal Efficiency and Power Density", www.intechopen.com.
  71. Han, J. C., "Recent Studies in Turbine Blade Cooling", International Journal of Rotating Machinery, Vol.10 No.6, 2004, pp.443-457.
  72. Ameral, S., Verstraete, T., Braembussche, R. V. and Arts, T., "Design and Optimization of the Internal Cooling Channels of a High Pressure Turbine Blade- Part I : Methodology", Journal of Turbomachinery, April 2010, Vol.132, pp.021013-1 to 021013-7.
  73. Verstraete, T., Amaral, S., Braembussche, R. V. and Arts, T., "Design and Optimization of the Internal Cooling Channels of a High Pressure Turbine Blade- Part II : Optimization, Journal of Turbomachinery, April 2010, Vol.132, pp.021014-1 to 021014-9.
  74. Zolfagharian, M. M., Zargarabadi, M. R., Majumdar, A. S., Valipoour, M. S. and Asadollahi, M., "Optimization of Turbine Blade Cooling Using Combined Cooling Techniques", Engineering Applications of Computational Fluid Mechanics, Vol.8, No.3, 2014, pp.462-475.
  75. Gupta, S., Chaube, A. and Verma, P., Review on Heat Transfer Augmentation Techniques: Application in Gas Turbine Blade Internal Cooling", Journal of Engineering Science and Technology Review, Vol.5, No.1, 2012, pp.57-62.
  76. Ligrani, P., "Heat Transfer Augmentation Technologies for Internal Cooling of Turbine Components of Gas Turbine Engines", International Journal of Rotating Machinery, Vol.2013 (2013), Article ID 275653, 32 pages.
  77. Ligrani, P. M., Oliveira, M. M. and Blaskovich, T., "Comparison of Heat Transfer Augmentation Techniques", AIAA Journal, Vol.41, No.3, 2003, pp. 337- 362.
  78. Nathan, S., "Jewel in the Crown: Rolls Royces Single Crystal Turbine Blade Casting Foundry", 8th June 2015. https://www.theengineer.co.uk/jewel-in-thecrown- rolls-royce-single-crystal-turbine blade-casting- foundry
  79. Felice, M., "Materials through the Ages: Materials for Aeroplane Engines" Materials World http: iom3.org/materialsworld-magazine/feature/2013/ may/09/materials- through-ages.
  80. Xie, G. N., Sunden, B., Wang, L. and Utriainen, E., "Enhanced Heat Transfer on the Tip-Wall in a Rectangular Two-Pass Channel by Pin-Fin Arrays", Numerical Heat Transfer-Part A, 2009, Vol.52, pp.739-761.
  81. Aerospace Engineering, "Jet-Engine Design: Turbine Cooling", May 1, 2013.
  82. Volume 1. Performance Flight Testing Phase Chapter 7 Aero Propulsion, Feb 1991, USAF Test Pilot School, Edwards AFB, CA, USA.
  83. Girardeau, J., Pailhas, J., Sebastian, P., Pardo, F. and Nadeau, J. P., "Turbine Blade Cooling System Optimization", Journal of Turbomachinery, Vol.135, Issue 6, 2013, pp.061020-1 to 061020-13.
  84. "The Jet Engine", Rolls Royce, 1996, Revised 2005 ISBN: 0902121235, 978090212123 2.
  85. Lakshminarayana, B., "Fluid Dynamics and Heat Transfer of Turbomachinery", 1996, John Wiley & Sons. ISBN: 0-471-85546-4.
  86. Nasir, H., "Turbine Blade Tip Cooling and Heat Transfer", Ph. D. Dissertation in Mechanical Engineering Department, Louisiana State University, December 2004.
  87. "6000-psi Waterjet Cutting Machines- Cuts Titanium Better than a Steel Blade or Drill", http://www.laser-cutting-online.com/waterjet-cutti ng-machines.html
  88. Hashish, M., "Abrasive Waterjet Drilling of High Temperature Jet Engine Parts", Paper No. PUP2009- 77365, pp. 65-73, ASME 2009 Pressure Vessels and Piping Conference.
  89. Waterjet Drilling, http://www.laico.com/companywaterjet- drilling.html.
  90. Wang, M. H., Zhu, D., Qu, N. S. and Zhang, C. Y., "Preparation of Turbulated Cooling Hole for Gas Turbine Blade using Electrochemical Machining", Key Engineering Materials, Vol.329, 2007, pp.699- 704.
  91. Coteata, M., Slatineanu, L., Dodun, O. and Ciofu, C., "Electrochemical Discharge Machining of Small Diameter Holes", International Journal of Material Forming, April 2008, pp.1327-1330.
  92. Youssef, H. A., "Machining of Stainless Steels and Super Alloys: Traditional and Non-Traditional Techniques", John Wiley and Sons, 2016, ISBN 978-1- 118-91956.
  93. Brule, A., Deschamps, J. B., Marco, M. D., Richerzhagen, B. and Levine, H. H., "Laser Microjet for High Precision Drilling of Mechanical Devices such as Fuel Injection Nozzles", Proceedings of LPM2008, The 9th International Symposium on Laser Precision Microfabrication.
  94. "GE, Synova and Makino Partner to Develop Advanced GT Manufacturing Machines", Modern Power Systems, 30 October 2014.
  95. Clarke, D. R., Oechsner, M. and Padture, N. P., "Thermal Barrier Coatings for More Efficient Gas Turbine Engines", MRS Bulletin, Vol.37, October 2012, pp.891-898.
  96. Sampath, S., Schulz, U., Jarligo, M. O. and Kuroda, S., "Processing Science of Advanced Thermal Barrier Systems", MRS Bulletin, Vol.37, October 2012, pp.903-910.
  97. Padture, N. P., Gell, M. and Jordan, E. H., "Thermal Barrier Coatings for Gas Turbine Engine Applications", Science, Vol.296, A2 April 2002, pp.280-284.
  98. Sourmail, T., "Coatings for Turbine Blades", University of Cambridge Website, June 5, 2006. http://www.msm.cam.ac.uk/phase-trans/2003/supe ralloys/coatings/index.html.
  99. "High Temperature Coatings", Wadley Research Group, Department of Materials Science and Engineering, University of Virginia. http://www.virginia. edu/ms/research/wadley/high-temp.html
  100. Schneibel, J. H., "Beyond Nickel-Base Superalloys", Proceedings of Processing and Fabrication of Advanced Materials XIII Conference, M. Gupta, T. S. Srivatsan, CYH Lin, R. A. Varin Editors, Stallion Press, Singapore, 2005, pp.563-576.
  101. Drawin, S. and Justin, J. F., "Advanced Lightweight Silicide and Nitride Based Materials for Turbo-Engine Applications", Journal Aerospace Lab, Issue 3, November 2011, Paper No.AL03-06, pp.1-13.
  102. Schneibel, J. H., Kruzic, J. J. and Ritchie, R. O., "Development of Ultra-High Temperature Molybdenum Borosilicides", Proceedings of the 20th Annual Conference on Fossil Energy Materials, June 12-14, 2006, Oak Ridge National Laboratory.
  103. Klemm, H., "Silicon Nitride for High Temperature Applications", Journal of the American Ceramic Society, Vol.93, 2010, pp.1501-1522.
  104. "Flightpath 2050, Europe’s Vision for Aviation", Report of the High Level Group on Aviation Research, European Commission, 2011, European Union, ISBN 978-92-79-19724-6.
  105. Gardiner, G., "Aeroengine Composites, Part 1: The CMC Invasion", Composites World, August 2015, pp.38-41.
  106. Wood, K., "Ceramic-Matrix Composites Heat Up", High Performance Composites, November 2013, pp.38-45.
  107. Xu, L., Bo, S., Hongde, Y. and Lei, W., "Evolution of Rolls-Royce Air-Cooled Turbine Blades and Feature Analysis", Procedia Engineering, Vol.99, 2015, pp.1482-1491.
  108. "GE Successfully Tests World’s First Rotating Ceramic Matrix Composite Material for Next-Gen Combat Engine", GE Aviation, February 10, 2015 http://www.geaviation./press/military/military_20 150210.html
  109. Hirano, K., "Application of Eutectic Composites to Gas Turbine System and Fundamental Fracture Properties up to 1700°C", J. European Ceramic Society, Vol.25, 2005, pp.1191-1199.
  110. Parlier, M., Valle, R., Perriere, L., Korinek, S. L. and Mazerolles, L., "Potential of Directionally Solidified Eutectic Ceramics for High Temperature Applications", Journal Aerospace Lab, Issue 3, November 2011, Paper Number AL03-07, pp.1-13.
  111. Takahashi, K., Ando, K. and Nakao, W., "Crack- Healing Ability of Structural Ceramics and Methodology to Guarantee the Reliability of Ceramic Components", in the Book, Advances in Ceramics- Characterization, Raw Materials, Processing, Properties, Degradation and Healing, Edited by Costas Sikalidis, ISBN 978-953-307-504-4, August 1, 2011.
  112. Raj, S. V., Singh, M. and Bhatt, R. T., "High Temperature Lightweight Self-Healing Ceramic Composites for Aircraft Engine Applications", NASA/TM 2014-218352, Glenn Research Center, October 2014.
  113. Garvie, R. C., Hannink, R. H. J., and Pascoe, R. T., "Ceramic Steel?", Nature (London), Vol.258, 1975, pp.703-704.