Titanium alloys: modelling of microstructure, properties and applications

Transcription

1 Titanium alloys: modelling of microstructure, properties and applications Wei Sha and Savko CRC Press Boca Raton Boston New York Washington, DC WOODHEAD PUBLISHING LIMITED Oxford Cambridge New Delhi

2 Author contact details Preface xi xiii 1 Introduction to titanium alloys Introduction Conventional titanium alloys Titanium aluminides Modelling Part I Experimental techniques 2 Microscopy High temperature microscopy of surface oxidation and transformations Gamma titanium aluminide Transmission electron microscopy of microstructural evolution Synchrotron radiation X-ray diffraction Introduction Measurements at room temperature Measurements at elevated temperatures Gamma titanium aluminide Differential scanning calorimetry and property measurements Phase and structural transformations Mechanical properties of ß21S alloy 83

3 VI 4.3 Effects of hydrogen penetration Part II Physical models 5 Thermodynamic modelling Introduction Conventional titanium alloys Titanium aluminides The Johnson-Mehl-Avrami method: isothermal transformation kinetics Introduction Resistivity experiments Metallography X-ray diffraction Additional ageing Thermodynamic equilibria Kinetics of the transformation Time-temperature-transformation diagrams Summary The Johnson-Mehl-Avrami method adapted to continuous cooling Introduction Interpretation of calorimetry data X-ray diffraction Microstructure and hardness Calculation of continuous-cooling-transformation diagrams Calculation of transformation kinetics Simulation and monitoring of transformations on continuous cooling Summary Finite element method: morphology of ß to a phase transformation Introduction Experimental and modelling methodology 204

4 VII 8.3 Experimental observation of the morphology of the phase transformation Mathematical formulation in the model for the microstructure of Ti-6A1-4V The 1-D model The 2-D model Summary of the models for Ti-6A1-4V Extending to other alloys Summary Phase-field method: lamellar structure formation in y-tial Introduction Mathematical formulation Computer simulation of lamellar structure formation in y-tial Summary Cellular automata method for microstructural evolution modelling Introduction Microstructural evolution of Ti-6A1-4V during thermomechanical processing The simulation model Simulated microstructural evolution during dynamic recrystallisation Simulated flow stress-strain behaviour Summary of the simulation method and its capabilities Crystallographic and fracture behaviour of titanium aluminide Introduction Single crystal characteristic Crack path analyses Transmission electron microscopy A model for microcracks nucleation in basal slip Summary

5 viii 12 Atomistic simulations of interfaces and dislocations relevant to TiAl Introduction Tasks Computational procedure Choice of interatomic potential Part III Neural network models 13 Neural network method Introduction Software description Use of the software Upgrading the software system Summary Neural network models and applications in phase transformation studies ß-transus temperature Time-temperature-transformation diagrams An example of MatLab program code for neural network training Neural network models and applications in property studies Correlation between processing parameters and mechanical properties Fatigue stress life (S-N) diagrams Mechanical properties of gamma-based titanium aluminides Reference Appendix 410 Part IV Surface engineering products 16 Surface gas nitriding: phase composition and microstructure Introduction Near-aTi-8Al-lMo-lV 417

6 Near-a Ti-6Al-2Sn-4Zr-2Mo a + ß Ti-6A1-4V Near-ß Ti-10V-2Fe-3Al ß21s Timetal 205 Ti-Al Summary of the effect of the parameters of gas nitriding on the microstructure Surface gas nitriding: mechanical properties, morphology, corrosion Hardness evolution Tensile properties and fatigue performance after nitriding Surface morphology and roughness of Ti-6Al-2Sn-4Zr-2Mo after nitriding Corrosion behaviour IX Nitriding: modelling of hardness profiles and the kinetics Artificial neural network modelling of microhardness profiles Kinetics of gas nitriding Aluminising: fabrication of Al and Ti-Al coatings by mechanical alloying Introduction As-synthesised state Annealing treatment of the aluminium coating Annealing treatment of titanium/aluminium coating Summary Index 549