Sha W., Malinov S. Titanium Alloys: Modelling of Microstructure, Properties and Applications

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Index562

β to α + β transformations

different mechanisms, 151

experimental and calculated

kinetics, 154

JMA kinetic parameters and

mechanisms, 153

kinetics, 122

finite element modeling test and

performance, 505

isothermal transformation diagram,

161

Johnson-Mehl-Avrami

β to α + β or β to α phase

transformation rate constant,

194

course of β to α transformation,

182

degree of β to α + β or β to α

phase transformation, 197

fully lamellae microstructure, 181

kinetic parameters, 146

microstructure after cooling, 175

parameters derivation, 144–5

regression analysis of degree of

transformation, 199

α-stabilising element Al

percentage, 181

Vickers microhardness, 180

metallography, 128

microhardness profiles

predicted values vs experimental,

505

temperature effects, 507

microstructure after isothermal

exposure, 126

microstructure evolution, 204

near-α, surface gas nitriding, 417–22

near-α, surface gas nitriding

hardness evolution, 450–1, 454

microhardness values, nitrided at

950 °C, 453

microhardness values, nitrided at

1050 °C, 454

microhardness values from surface

to the core, 453

near-α, surface gas nitriding

microstructure, 420–2

microstructure after nitriding, 421

near-α, surface gas nitriding

nitrided layer thickness and

temperature, 452–3

near-α, surface gas nitriding

phase composition, 417–20

near-α, surface gas nitriding

surface hardness, 451

variation in microhardness values,

454

weight loss vs time after holding

in 4.9M HCL, 493

near-α, surface gas nitriding

XRD pattern after nitriding at 950

°C, 418

XRD pattern after nitriding at 1050

°C, 419

numerical simulation

after nitriding at 950 °C, 525–6

during nitriding at 840 and 920 °C,

527

α phase

amounts vs temperature, 136

volume fractions, 138

phase composition at various

temperatures, 137

thermodynamic equilibria, 135–6, 138

thermodynamics modelling, 98–100

β phase fractions equilibrium vs

temperature, 108

calculated equilibria vs

temperature, 99–100

characteristic transformation

temperature variation, 110

transformation kinetics, 150–2, 154

TTT diagrams, 161

typical resistivity curve, 119

AlNb, 4

Ti–6Al–7Nb alloy

Johnson-Mehl-Avrami method

β to α + β or β to α phase

transformation rate constant,

194

calorimetry curve, 167

calorimetry data interpretation, 171

calorimetry peak parameters, 169

CCT diagram, 189

cooling rate effect on lamellar

thickness and hardness, 179

course of β to α transformation,

182–3

Index 563

degree of β to α + β or β to α

phase transformation, 197

microstructure after cooling, 177

regression analysis of degree of

transformation, 200

thermo-kinetics diagram, 186

thermodynamics modelling, 101–2

β phase fractions equilibrium vs

temperature, 109

calculated equilibria vs

temperature, 103–4

characteristic transformation

temperature variation, 111

Ti–42Al–11Nb alloy, 86

Ti–46.5Al–5Nb alloy

predicted vs experimental tensile

strength, 406

Ti–6Al–2Sn–4Sn–2Mo alloy

numerical simulation during nitriding

at 840 °C, 528

Ti–6Al–2Sn–4Zr–2Mo alloy, 3, 470–86

β to α + β transformations JMA

kinetic parameters, 148

β to α phase transformation

barrier for nucleation and rate of

nucleation, 234

FEM simulation for microstructure

evolution, 235

2D surface morphology

before and after nitriding at 950

°C, 1 hour, 479

before and after nitriding at 950

°C, 3 hours, 480

before and after nitriding at 950

°C, 5 hours, 481

before and after nitriding at 1050

°C, 5 hours, 482

of polished alloy, 475

using abrasive paper #220, 473

using abrasive paper #2400, 474

3D surface morphology

before and after nitriding at 950

°C, 1 hour, 483

before and after nitriding at 950

°C, 3 hours, 483–4

before and after nitriding at 950

°C, 5 hours, 484

before and after nitriding at

1050 °C, 5 hours, 485

of polished alloy, 477

using abrasive paper #220, 476

using abrasive paper #2400,

476–7

etched, microscopic image, 12

Johnson-Mehl-Avrami method

CCT diagram, 171

metallography, 124, 127

microhardness profiles, 485

gas mixture effects, 508

time of nitriding effects, 506

microstructure

after continuous cooling, 207

after nitriding, 487

evolution, 204

near-α, surface gas nitriding, 423–5,

427

DSC and TG curves, 424

hardness evolution, 454–5, 455

microhardness profile after

nitriding at 850 °C, 456

microhardness profile after

nitriding at 950 °C, 456

microhardness profile after

nitriding at 1050 °C, 457

microhardness profiles, 456–7

microstructure, 424–5, 427

microstructure after nitriding, 426

phase composition, 423–4

SEM micrograph and positions of

scan, 425

surface hardness, 455

XRD pattern after nitriding at 950

°C, 425

XRD pattern after nitriding at 1050

°C, 423

nitrogen concentration profile in

diffusion layer

different times of nitriding at 950

°C, 521

phase modifications and

microstructure, 478

roughness before and after nitriding,

472

roughness of polished alloy under

different conditions, 478

in situ high temperature microscopy

image, 208

thermodynamics modelling, 96–7

Index564

calculated driving force for α

phase formation, 112

calculated equilibria vs

temperature, 98

transformation kinetics, 141, 146–8,

150

TTT diagrams, 156, 158, 160

TTT diagrams for start of β to α + β

transformation

calculated and experimental, 356

increased and decreased zirconium

content, 355

volume fractions of α phase, 138

weight loss vs time after holding in

4.9M HCL, 491

weight loss vs time after holding in

1.8M H

, 493

XRD pattern after nitriding at 950 °C,

486

Ti–6Al–2Sn–4Zr–6Mo alloy, 3

fatigue strength, 325

Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy

TTT diagrams for start of β to α + β

transformation

different tin and chromium levels,

354

Ti–6Al–2Sn–4Zr–2Mo–0.08Si alloy, 3

β to α + β transformations

calculated start, 160

experimental and calculated

kinetics, 149

JMA rate constants, 147

kinetics, 121

calculated TTT diagrams, 159

Johnson-Mehl-Avrami method

β to α + β or β to α phase

transformation rate constant,

193

calculated kinetics of β to α phase

transformation, 202

calorimetry curve, 166

calorimetry data interpretation,

168, 170

calorimetry peak parameters, 169

CCT diagram, 188

course of β to α transformation,

182

degree of β to α + β or β to α

phase transformation, 196

kinetic parameters, 146

microstructure after cooling, 174

parameters derivation, 142–3

α phase lattice parameters, 173

regression analysis of degree of

transformation, 199

thermo-kinetics diagram, 185

X-ray diffraction pattern after

cooling, 172

measurements at elevated

temperatures

alloy surface transformations, 51–2

temperature and oxygen effect on

lattice parameters, 52

microstructure after isothermal

exposure, 125

α phase amounts vs temperature, 135

phase composition at various

temperatures, 134

surface microstructure, 12

synchrotron radiation X-ray

diffraction

β phase fractions vs temperature

for different oxygen levels, 46

diffraction patterns at different

temperatures, 44

diffraction patterns at room

temperature, 35

full-width half maximum for α

reflections, 40

measurements at elevated

temperatures, 50–2

measurements at room

temperature, 40–1

surface oxidation kinetics at 600

°C, 51

transformation kinetics during

isothermal exposure at 600 °C,

thermodynamic equilibria, 133

typical resistivity curve, 118

Ti–5.8Al–4Sn–3.5Zr–0.7Nb–0.5Mo–

0.35Si alloy

Johnson-Mehl-Avrami method

β to α + β or β to α phase

transformation rate constant,

194

course of β to α transformation,

183

Index 565

lamellar thickness variation, 178

microstructure after cooling, 176

regression analysis of degree of

transformation, 200

Vickers microhardness, 180

thermodynamics modelling, 100

β phase fractions equilibrium vs

temperature, 108

calculated equilibria vs

temperature, 101–2

characteristic transformation

temperature variation, 110

Ti–Al–V alloy

TTT diagrams for start of β to α + β

transformation

different Al and V contents, 351

Ti–6Al–4V alloy, 3

α + β, surface gas nitriding, 427

DSC curves, 430

fatigue strength, 471

hardness evolution, 455

influence of nitriding on tensile

strength, 470

microhardness profile after

nitriding at 850 °C, 458

microhardness profile after

nitriding at 950 °C, 458

microhardness profile after

nitriding at 1050 °C, 459

microstructure, 427

microstructure after nitriding, 431

phase composition, 427

SEM image after nitriding, 469

SEM images of compound layer,

432

surface hardness, 457

XRD pattern after nitriding at 950

°C, 428

XRD pattern after nitriding at 1050

°C, 429

β to α + β transformations

experimental and calculated

kinetics, 149

JMA kinetic parameters, 148

JMA rate constants, 147

kinetics, 121

β to α phase transformation

barrier for nucleation and rate of

nucleation, 219

1-D model, 218–23

2-D model, 223–4, 227–8, 230,

232–3

kinetics for different cooling rates,

222

calculated TTT diagrams, 159

fatigue stress life diagrams, 388–96

calculated vs experimental data,

391, 393, 395

graphical user interface, 396

model description, 388–9

test and performance, 390

FEM simulations of microstructure

evolution

at 5 °C/min cooling rate, 228–9

at 10 °C/min cooling rate, 224–5

at 30 °C/min cooling rate, 225–6

under isothermal conditions, 230–2

Johnson-Mehl-Avrami method

β to α + β or β to α phase

transformation rate constant,

193

calorimetry curve, 166

calorimetry data interpretation,

166–8

calorimetry peak parameters, 169

CCT diagram, 187

course of β to α transformation,

182

degree of β to α + β or β to α

phase transformation, 196

kinetic parameters, 146

microstructure after continuous

cooling, 170

parameters derivation, 142–3

regression analysis of degree of

transformation, 199

thermo-kinetics diagram, 185

X-ray diffraction pattern after

cooling, 184

mathematical formulation in

microstructure model, 206–18

α/β interface localisation, 213–15

FEM formulation of diffusion

problem, 215–18

nucleation, 208–10

phase lamellae growth, 210–13

measurements at elevated

temperatures

Index566

alloy surface transformations, 45–9

temperature and oxygen effect on

lattice parameters, 50

metallography, 127

microstructural evolution

calculated stress evolution curves,

268

dislocation density fluctuation, 269

flow stress–strain behaviour, 266–7

modeling by cellular automata

method, 258–70

simulation method and its

capabilities, 267–70

simulation model, 263–5

during thermomechanical

processing, 259–63

microstructure

after cooling, 221

after hot pressing at 1050 °C with

0.5 s

–1

strain rate, 268

after isothermal exposure, 125

evolution, 204

α phase

amounts vs temperature, 135

volume fractions, 138

phase composition at various

temperatures, 134

real nucleation rate FEM simulation,

222

simulated microstructure

at 1050 °C and 1 s

–1

strain rate,

266

at 1050 °C and true strain of 10,

267

at different temperatures and

strains, 267

during dynamic recrystallisation,

265

in situ high temperature microscopy

image, 208

summary of models, 233

synchrotron radiation X-ray

diffraction

β phase fractions vs temperature

for different oxygen levels, 46

different heat treatment conditions

diffraction pattern, 37–8

diffraction patterns at different

temperatures, 43

diffraction patterns at room

temperature, 34

full-width half maximum for α

reflections, 40

measurements at elevated

temperatures, 45–50

measurements at room

temperature, 35–8, 40

surface oxidised layer

microstructure, 47

transformation kinetics during

isothermal exposure at 600 °C,

Thermo-Calc and FEM amounts of α

phase, 232

thermodynamic equilibria, 133

thermodynamics modelling, 96

calculated driving force for α

phase formation, 112

calculated equilibria vs

temperature, 97

thermomechanical processing

dynamic crystallisation, 262–3

dynamic recrystallisation

micrographs, 263

flow stress–strain curves, 259–60

micrographs of hot-pressed

samples, 261

α phase different morphologies, 262

phase transformation, 261

stress–strain curves of hot-pressed

specimen, 259

variation of flow stress, 260

transformation kinetics, 141, 146–8,

150

TTT diagrams, 156, 158, 160

TTT diagrams for start of β to α + β

transformation

different oxygen levels, 352

typical resistivity curve, 118

unetched

microscopic image development at

high temperatures, 13

observed morphology of β to α

transformations, 14

surface oxidation kinetics during

isothermal exposure, 16

V concentration profile at α/β

interface, 211

Index 567

Ti-2.5Cu

TTT diagrams for start of β to α + β

transformation, 360

Ti-database, 42, 54

Timetal 205 alloy, 4

hardness evolution, 462–4

microhardness profile after nitriding at

730 °C, 464

microhardness profile after nitriding at

830 °C, 464

surface gas nitriding, 438–9, 442

hardness evolution, 462–4

microhardness profiles, 464

microstructure using optical

microscopy, 439, 442

optical micrographs after nitriding

at 730 °C, 445

optical micrographs after nitriding

at 830 °C, 445

XRD analysis, 438–9

XRD pattern after nitriding at 730

°C, 443

XRD pattern after nitriding at 830

°C, 444

XRD pattern of untreated alloy,

442

TIMETAL β21s, thermodynamics

modelling, 102–3

time–temperature-transformation

diagrams, 156–62, 343–61

Al and V influence on β phase

decomposition, 351

for alloys without available diagrams

in literature, 360

β to α + β transformation in titanium

alloys, 357–9

β21s, 161–2

digitisation, 345

distribution of input data set, 344

influence of alloying elements on

titanium alloys, 348, 350–6

Al and V, 348, 350

Mo, 351, 353

oxygen, 350

tin and chromium, 353

zirconium, 353

log-sigmoid transfer function, 347

Mo influence on β phase

decomposition, 352

model description, 343–8

database, analysis and pre-

processing, 343–6

training, 346–8

neural network architecture for nose

point simulation, 346

oxygen influence on β phase

decomposition, 352

prediction for commercial alloys, 356

statistical analysis of variables, 344

tan-sigmoid transfer function, 347

Ti–8Al–1Mo–1V, 161

Ti–6Al–4V and Ti–6Al–2Sn–4Zr–

2Mo, 156, 158, 160

tin and chromium influence on β

phase decomposition, 354

training and testing performance, 349

upper and lower part simulation, 347

whole datasets performance, 350

zirconium and iron influence on β

phase decomposition, 355

Ti–15Mo–3Al–2.7Nb–0.25Si see β21s

alloy

Ti–15Mo–5Zr–3Al alloy

microhardness profiles predicted

values vs experimental, 504

titanium alloy, 1–8, 54–68, xiii–xiv see

also specific alloy

advantages and disadvantages, 1

Al and Mo equivalent values, 108

applications, 1

atomistic simulation, xiii

basic principles of corrosion, 487–9

corrosion resistance enhancement,

489

corrosion resistance mechanism,

488

general corrosion, 487–8

reducing acids, 489

salt solutions, 488

characteristics and typical

composition, 5

classification, 2–3

conventional, 2–4

microstructure and properties, 2–3