Materials and Strength of Gas Turbine Parts: Volume 1: Materials, Properties, Damage, Deformation and Fracture Models (Advanced Structured Materials, 150)

This book discusses several mechanical and material problems that are typical for gas turbine components. It discusses accelerated tests and other methods for increasing the reliability of gas turbine engines. Special attention is given to non-traditional methods for calculating the strength characteristics and longevity of the main components. This first volume focuses on the selection of materials, deformation and destruction mechanisms in connection with stationary and non-stationary loading, and types of material damage such as the thermal fatigue. Particular attention is paid to the issues of the properties of single crystal alloys, the relationship between structure and properties, the influence of technological factors and long-term operation. The characteristics of creep resistance, crack resistance, and resistance to cyclic deformation of different alloys are given. Foreword Preface References Volume 1: Materials, Properties, Damage, Deformation and Fracture Models Contents Acronyms About the Author Chapter 1 Operation Conditions of Gas Turbine Parts and Materials used for them 1.1 Operation Conditions of High-temperature Components of Gas Turbine Units and Damage Mechanisms During Long-term Operation and Laboratory Testing 1.1.1 Turbine Guide Blades 1.1.2 TurbineWorking Blades 1.1.3 Turbine Disks 1.1.4 Stator Components 1.1.5 Compressor Blades, Disks, and Housings 1.1.6 Reduction Gears 1.2 Requirements for the Materials of Gas Turbine Units Components 1.2.1 Turbine Disks 1.2.2 TurbineWorking Blades 1.2.3 Turbine Guide Blades 1.2.4 Flame Tubes 1.2.5 Fasteners 1.2.6 Regenerators 1.2.7 Blades, Disks and Compressor Housings 1.3 Materials of Gas Turbine Unite Components 1.3.1 Perlitic Steels 1.3.2 Ferritic Steels 1.3.3 Austenitic Steels 1.3.4 Nickel, Nickel-Cobalt, and Cobalt Based Alloys 1.3.5 Composite Materials 1.3.6 Ceramic Materials 1.3.7 Titanium Alloys 1.4 Concluding Remarks References Chapter 2 Deformation and Strength of Heat-resistant Materials under Static and Cyclic Loading 2.1 Mechanical Behavior under Uni-axial Stress State 2.1.1 Elasticity and Plasticity 2.1.2 Young’s Modulus 2.1.3 Heterogeneity of Plastic Deformations 2.1.4 Scale Factor 2.2 Creep and Stress Relaxation 2.2.1 Creep Phenomenon 2.2.2 Creep Theories 2.2.3 Isochronous Creep Curves 2.2.4 Stress Relaxation 2.3 Multi-axial Strain and Stress States 2.3.1 Elasticity 2.3.2 Stress Concentrations 2.3.3 Simplest Models of Ductility and Creep 2.4 Resistance of Materials to Cyclic Deformation 2.4.1 Cyclic Elasto-plastic Deformation 2.4.2 Cyclic Elasticity Limit 2.4.3 Cyclic Creep and Stress relaxation Under Constant Sign Loading 2.4.4 Cyclic Creep Under Alternating Stress 2.4.5 Cyclic Creep Under Varying Temperature 2.4.6 Cyclic Elasto-Plasticity Under Varying Temperature 2.5 Strain Theories at Complex Loading 2.5.1 Effects of the Behavior of Metallic Materials 2.5.2 Models of Visco-Elasto-Plasticity 2.5.3 Implementation of Cyclic Plasticity and Creep Models under Proportional Loading 2.6 Concluding Remarks References Chapter 3 Deformation Response of Heat Resistant Materials at Static and Cyclic Loading 3.1 Ductile and Brittle Fracture Criteria 3.1.1 Fracture Criteria 3.1.2 Conditions for Ductile and Brittle Fracture 3.1.3 Bearing Capacity of Structures 3.2 Long-term Strength at Constant and Variable Temperatures and Stresses 3.2.1 Time Dependency 3.2.2 Influence of Temperature 3.2.3 Damage Mechanisms and Deformation Capacity of Materials During Creep 3.2.4 Fracture Under Stress Relaxation Conditions 3.2.5 Long-term Strength Under Complex Stress State 3.2.6 Long-term Strength at Variable Temperatures and Stresses 3.3 Resistance to Fracture for Cyclically Varying Stresses 3.3.1 High Frequency Fatigue 3.3.2 Low Cycle Fatigue 3.3.3 Thermal Fatigue 3.4 Failure Criteria for Complex Loading Programs 3.4.1 Damage Under Static and Low-cycle Loading 3.4.2 Fracture Criteria for Elasto-plastic Deformation 3.4.3 Adaptability Theory 3.4.4 Failure Criterion for Alternating Cyclic Creep 3.4.5 Modified Fracture Criteria for Materials Under Cyclic Loading 3.4.6 Experimental Verification of Criteria 3.4.7 Fracture Criteria for Complex Stress State 3.5 Features of the Formation and Propagation of Cracks in Heat-resistant Alloys under Static and Dynamic Loading 3.5.1 Conditions and Nature of Cracking 3.5.2 Crack Propagation Rate 3.6 Concluding Remarks References Chapter 4 Influence of Technological Factors and Long-term Operation on the Microstructure and Properties of Heat-resistant Materials 4.1 Dependence of Properties on Metallurgical Factors, Size, and Orientation of Grains 4.1.1 Influence of Melting and Casting Methods 4.1.2 Influence of Deformation Conditions of Workpiece 4.1.3 Effect of Grain Size of Deformed Alloys 4.2 Influence of Crystal Orientation on the Properties of Cast Alloys 4.2.1 Microstructure of Monocrystalline Materials 4.2.2 Anisotropy of Elastic Moduli 4.2.3 Poisson’s Ratio Anisotropy 4.2.4 Anisotropy of the Coefficient of Thermal Expansion 4.2.5 Short-term Mechanical Properties 4.2.6 Resistance to High Frequency Fatigue 4.2.7 Long-term Strength and Creep Resistance 4.2.8 Thermal and Low-cycle Fatigue 4.2.9 Fracture Criteria for Monocrystalline Materials under Thermal Cyclic Loading 4.2.10 Crystallographic Features of High-cycle Fatigue Fracture of Single Crystals 4.2.11 Oxidation Resistance 4.3 Relationship of Structure and Properties 4.3.1 Influence of Heat Treatment Regime 4.3.2 Effects of Long-term Aging 4.3.3 Reductive Heat Treatment 4.4 Dependence of Properties on the State of the Surface 4.4.1 Effect of Mechanical and Heat Treatment on the State of the Surface Layer 4.4.2 Dependence of Properties on Surface Condition 4.4.3 Methods of Surface Hardening of Gas Turbine Parts 4.5 Concluding Remarks References Appendix A Russian Steels and Alloys for Gas Turbine Units Appendix B Isochronous Creep Curves B.1 Materials and Test Conditions B.2 Diagrams Appendix C Cyclic Creep Curves C.1 Materials and Test Conditions C.2 Diagrams Appendix D Fracture Toughness Characteristics at Cyclic Load D.1 Materials and Their Parameters D.2 Cyclic Fracture Toughness Curves References