Interface of Ceramic-Matrix Composites

Longbiao Li, PhD, is a lecturer in the College of Civil Aviation at the Nanjing University of Aeronautics and Astronautics (NUAA). His research focuses on the fatigue, damage, fracture, reliability, and durability of aircraft and aero engine. In this research area, he is the first author of 128 SCI journal publications, 2 monograph, 3 book chapters, 10 Chinese Patents, and 1 US Patent, and more than 20 refereed conference proceedings. He has been involved in different projects related to structural damage, reliability, and airworthiness design for aircraft and aero engines, supported by the Natural Science Foundation of China, COMAC Company, and AECC Commercial Aircraft Engine Company.

• Preface xiAcknowledgments xiii1 Definition, Function, and Design of Interface in Ceramic-Matrix Composites 11.1 Introduction 11.2 The Definition of Interface in Ceramic-Matrix Composites 21.2.1 Non-oxide CMCs 31.2.2 Oxide/Oxide CMCs 131.3 The Function of Interface in Ceramic-Matrix Composites 181.3.1 Effect of Interphase on Sliding Resistance 191.3.2 Effect of Interphase on Thermal Misfit Stress 191.4 The Design of Interface in Ceramic-Matrix Composites 201.4.1 PyC Interphase 201.4.2 BN Interphase 211.5 Conclusion 21References 222 Interface Characterization of Ceramic-Matrix Composites 292.1 Introduction 292.2 Effect of Interface Properties on Tensile and Fatigue Behavior of Ceramic-Matrix Composites 302.2.1 Theoretical Analysis 312.2.1.1 First Matrix Cracking Stress 312.2.1.2 Matrix Cracking Density 312.2.1.3 Fatigue Hysteresis-Based Damage Parameters 322.2.2 Results and Discussion 332.2.2.1 Effect of the Interface Properties on First Matrix Cracking Stress 332.2.2.2 Effect of the Interface Properties on Matrix Cracking Density 362.2.2.3 Effect of the Interface Properties on the Fatigue Hysteresis-Based Damage Parameters 392.2.3 Experimental Comparisons 412.2.3.1 First Matrix Cracking Stress 422.2.3.2 Matrix Cracking Density 432.2.3.3 Fatigue Hysteresis-Based Damage Parameters 462.3 Effect of Pre-exposure on Tensile Damage and Fracture of Ceramic-Matrix Composites 512.3.1 Theoretical Analysis 522.3.1.1 Stress Analysis Considering Interface Oxidation and Fiber Failure 542.3.1.2 Matrix Multicracking Considering Interface Oxidation 562.3.1.3 Interface Debonding Considering Interface Oxidation 572.3.1.4 Fiber Failure Considering Interface and Fiber Oxidation 582.3.1.5 Tensile Stress–Strain Curves Considering Effect of Pre-exposure 592.3.2 Results and Discussion 602.3.2.1 Effect of Pre-exposure Temperature on Tensile and Damage Process 602.3.2.2 Effect of Pre-exposure Time on Tensile and Damage Processes 612.3.2.3 Effect of Interface Shear Stress on Tensile and Damage Processes 622.3.2.4 Effect of Fiber Strength on Tensile and Damage Processes 642.3.2.5 Effect of FiberWeibullModulus on Tensile and Damage Processes 652.3.3 Experimental Comparisons 662.4 Effect of Interface Properties on Lifetime of Ceramic-Matrix Composites 712.4.1 Theoretical Analysis 73                                                                             2.4.1.1 Life Prediction Model at Room Temperature 742.4.1.2 Life Prediction Model at Elevated Temperatures in the Oxidative Environment 772.4.2 Experimental Comparisons 792.4.2.1 Life Prediction at Room Temperature 792.4.2.2 Life Prediction at Elevated Temperature 892.5 Conclusion 100References 1033 Interface Assessment of Ceramic-Matrix Composites 1093.1 Introduction 1093.2 Relationships Between Interface Slip and Temperature Rising in CMCs 1123.2.1 HysteresisTheories 1123.2.1.1 Case I 1133.2.1.2 Case II 1153.2.1.3 Case III 1163.2.1.4 Case IV 1173.2.2 Experimental Comparisons 1183.2.2.1 Unidirectional CMCs 1183.2.2.2 Cross-Ply CMCs 1223.2.2.3 2D CMCs 1243.3 Interface Assessment of CMCs from Hysteresis Loops 1273.3.1 Results and Discussion 1283.3.1.1 Unidirectional C/SiC Composite 1293.3.1.2 Cross-Ply C/SiC Composite 1313.3.1.3 2.5D C/SiC Composite 1353.3.2 Experimental Comparisons 1383.3.2.1 Unidirectional C/SiC Composite 1383.3.2.2 Unidirectional SiC/CAS Composite 1423.3.2.3 Unidirectional SiC/CAS-II Composite 1443.3.2.4 Cross-Ply C/SiC Composite 1443.3.2.5 2.5D C/SiC Composite 1493.4 Conclusion 155References 1564 Interface Damage Law of Ceramic-Matrix Composites 1614.1 Introduction 1614.2 Interface Damage Law at Room Temperature 1634.3 Interface Damage Law at Elevated Temperature in Inert Atmosphere 1674.4 Interface Damage Law at Elevated Temperature in Air Atmosphere 1724.4.1 1000 ∘C 1724.4.2 1200 ∘C 1754.4.3 1300 ∘C 1784.5 Interface Damage Law at Elevated Temperature in Steam Atmosphere 1854.5.1 1000 ∘C 1854.5.2 1200 ∘C 1874.6 Results and Discussion 1924.6.1 Effect of Temperature, Oxidation, and Fiber Preforms on Interface Damage of CMCs 1924.6.2 Comparisons of Interface Damage Between C/SiC and SiC/SiC Composites 1934.7 Conclusion 195References 196Index 199