Phase Transformations in Steels

The processing-microstructure-property relationships in steels continue to present challenges to researchers because of the complexity of phase transformation reactions and the wide spectrum of microstructures and properties achievable. This major two-volume work summarises the current state of research on phase transformations in steels and its implications for the emergence of new steels with enhanced engineering properties. Volume 1 reviews fundamentals and diffusion-controlled phase transformations. After a historical overview, chapters in part one discuss fundamental principles of thermodynamics, diffusion and kinetics as well as phase boundary interfaces. Chapters in part two go on to consider ferrite formation, proeutectoid ferrite and cementite transformations, pearlite formation and massive austenite-ferrite phase transformations. Part three discusses the mechanisms of bainite transformations, including carbide-containing and carbide-free bainite. The final part of the book considers additional driving forces for transformation including nucleation and growth during austenite-to-ferrite phase transformations, dynamic strain-induced ferrite transformations (DIST) as well as the effects of magnetic fields and heating rates. With its distinguished editors and distinguished international team of contributors, the two volumes of Phase transformations in steels is a standard reference for all those researching the properties of steel and developing new steels in such areas as automotive engineering, oil and gas and energy production.

Part I: Fundamentals of phase transformations Chapter 1: The historical development of phase transformations understanding in ferrous alloys Abstract: 1.1 Introduction 1.2 The legacy of ferrous technology, characterization, and understanding prior to 1880 1.3 The recognition of ferrous phase transformations in the first period (1880-1925) 1.4 The consolidation of ferrous phase transformations in the second period (1925-1970) 1.5 Conclusion 1.6 Bibliography Chapter 2: Thermodynamics of phase transformations in steels Abstract: 2.1 Introduction: the use of thermodynamics in phase transformations 2.2 External and internal variables 2.3 The state of equilibrium 2.4 The combined first and second law - its application 2.5 The calculation of thermodynamic properties and equilibrium under fixed T, P and composition 2.6 Gibbs energy of phases in steel - the Calphad method 2.7 Various kinds of phase diagrams 2.8 Effect of interfaces 2.9 Thermodynamics of fluctuations in equilibrium systems 2.10 Thermodynamics of nucleation Chapter 3: Fundamentals of diffusion in phase transformations Abstract: 3.1 Introduction 3.2 Driving forces of simultaneous processes 3.3 Atomistic model of diffusion 3.4 Change to a new frame of reference 3.5 Evaluation of mobilities 3.6 Trapping and transition to diffusionless transformation 3.7 Future trends 3.8 Acknowledgement Chapter 4: Kinetics of phase transformations in steels Abstract: 4.1 Introduction 4.2 General kinetic models 4.3 Geometrical/microstructural aspects in kinetics 4.4 Nucleation 4.5 Growth 4.6 Experimental methods 4.7 Industrial relevance 4.8 Acknowledgements Chapter 5: Structure, energy and migration of phase boundaries in steels Abstract: 5.1 Introduction 5.2 Atomic structure of phase boundaries 5.3 Free energies of phase boundaries 5.4 Migration of phase boundaries 5.5 Conclusions and future trends Part II: Diffusion-controlled transformations Chapter 6: Fundamentals of ferrite formation in steels Abstract: 6.1 Introduction 6.2 Crystallography 6.3 Transformation ranges 6.4 Nucleation 6.5 Growth 6.6 Conclusions Chapter 7: Proeutectoid ferrite and cementite transformations in steels Abstract: 7.1 Introduction 7.2 Temperature-composition range of formation of proeutectoid ferrite and cementite 7.3 The Dubé morphological classification system 7.4 Three-dimensional morphological classifications 7.5 Crystallographic orientation relationships with austenite 7.6 Habit plane, growth direction and interfacial structure of proeutectoid precipitates 7.7 Future trends 7.8 Source of further information and advice 7.9 Acknowledgements Chapter 8: The formation of pearlite in steels Abstract: 8.1 Introduction 8.2 An overview of the pearlite reaction 8.3 Crystallographic aspects of the reaction 8.4 The role of alloying elements 8.5 The deformation of pearlite 8.6 Future trends in pearlitic steels 8.7 Sources of further information and advice 8.8 Acknowledgements Chapter 9: Nature and kinetics of the massive austenite-ferrite phase transformations in steels Abstract: 9.1 Introduction 9.2 Kinetic information based on thermal analysis 9.3 Modular phase transformation model 9.4 Characteristics of normal and abnormal transformations 9.5 Kinetics of the normal transformation 9.6 Kinetics of the abnormal transformation 9.7 Transition from diffusion-controlled growth to interface-controlled growth 9.8 Transition from interface-controlled growth to diffusion-controlled growth 9.9 Massive transformation under uniaxial compressive stress 9.10 Conclusion Part III: Bainite and diffusional-displacive transformations Chapter 10: Mechanisms of bainite transformation in steels Abstract: 10.1 Introduction 10.2 Bainite: general characteristics 10.3 Diffusion-controlled growth mechanism 10.4 Displacive mechanism of transformation 10.5 Summary and conclusion Chapter 11: Carbide-containing bainite in steels Abstract: 11.1 Definitions of bainite structure 11.2 Crystallography and related characteristics of ferrite in bainite 11.3 Characteristics of carbide precipitation in bainite structure 11.4 Future trends Chapter 12: Carbide-free bainite in steels Abstract: 12.1 Introduction 12.2 Influence of silicon on cementite precipitation in steels 12.3 Carbon distribution during the carbide-free bainite reaction 12.4 Microstructural observations of plastic accommodation in carbide-free bainite 12.5 Conclusions 12.6 Acknowledgement Chapter 13: Kinetics of bainite transformation in steels Abstract: 13.1 Introduction 13.2 Transformation diagrams 13.3 Nucleation and growth of bainite 13.4 Start temperature of bainite 13.5 Effect of alloying elements 13.6 Overall kinetics 13.7 Conclusions 13.8 Acknowledgement Part IV: Additional driving forces for transformations Chapter 14: Nucleation and growth during the austenite-to-ferrite phase transformation in steels after plastic deformation Abstract: 14.1 Introduction 14.2 Background 14.3 Experiments and simulations on the effect of plastic deformation on ferrite formation 14.4 Future trends and conclusion Chapter 15: Dynamic strain-induced ferrite transformation (DSIT) in steels Abstract: 15.1 Introduction 15.2 What limits grain refinement in conventional static transformation? 15.3 Ultrafine ferrite formation in steels 15.4 Nature of the transformation 15.5 Modelling 15.6 Can grain sizes less than 1 -m be achieved? 15.7 Industrial implementation 15.8 Future trends 15.9 Conclusions 15.10 Acknowledgements Chapter 16: The effect of a magnetic field on phase transformations in steels Abstract: 16.1 Introduction 16.2 Evolution of the magnetic field generators 16.3 Basic mechanisms of field influence on a phase transformation in steels 16.4 Effect of magnetic field on phase equilibrium and transformation 16.5 Future trends and conclusions Chapter 17: The effect of heating rate on reverse transformations in steels and Fe-Ni-based alloys Abstract: 17.1 Introduction 17.2 Effect of heating rate on austenite formation in steels 17.3 Effect of heating rate on austenite microstructure after - - -(-ïEUR-) - - phase transformations in quenched steels 17.4 Effect of rapid heating on mechanical properties of steels and its applications 17.5 Effect of heating rate on the reverse austenite transformation in Fe-Ni-based alloys 17.6 Conclusions Index