Deformation Processes in TRIP/TWIP Steels (eBook)

Preface 7
Acknowledgements 9
Contents 12
Abbreviations 16
Symbols 21
Plastic Deformation 21
Martensitic Phase Transformation 23
Advanced High Strength Steels 24
In Situ Techniques Acoustic Emission a Radius A/left( f /right) Transfer function (after Fourier transformation) /vec{b} Burgers vector c_{{/rm L}} Velocity of longitudinal wave c_{T} Velocity of transversal wave C_{i,/,/,j,/,/,k,/,/,l} Elastic stiffness tensor D Duration of AE event D_{ij} Force dipoles D Measure of distance D_{{/rm EUC}} Euclidean distance D_{{/rm MAN}} Manhattan distance D_{MIN} Minkowski distance /hbox{d}A_{l} /left( t /right) Time-dependent dislocation loop area /hbox{d}B_{AE} Decibel of acoustic emission E AE energy E/left( f /right) Source function (after Fourier transformation) E/left( {f_{1} ,f_{2} } /right) Narrow band energy f Frequency f_{{/rm a}} Averaged frequency f_{{/rm c}} Fundamental frequency f_{{/rm eff}} Effective width of spectrum f_{i} Observed frequency f_{{/rm m}} Median frequency f_{{/rm N}} Nyquist frequency (cut-off frequency) F_{i} Expected frequency G/left( f /right) Power spectral density function G^{{/rm noise}} /left( f /right) Power spectrum of electrical noise G_{{/rm max}} Maximum of power spectral density function G^{i} /left( f /right) Integrated power spectral density function G_{ij} Green’s function G^{{/rm H}} Heaviside Green’s function g/left( f /right) Normalized power spectral density function i , j , k , l Space variables K Number of class intervals K_{{/rm u},/,/,{/rm PA}} Gain of used pre-amplifier /hat{k} Space–time variable k Number of desired clusters k_{i} , k_{j} Individual clusters m Activity of acoustic emission (AE) m_{i} , m_{j} Centroids of individual clusters n_{i} , n_{j} Number of elements within each individual clusters N Number of counts, number of observations N Length of time-series {/Delta }N Number of AE hits P/left( x /right) Probability distribution function p_{1} , p_{2} , p_{3} Point coordinates q_{1} , q_{2} , q_{3} Point coordinates q_{{/rm f}} Kurtosis (frequency domain) q_{{/rm x}} Kurtosis (time domain) r Number of independent variables r Distance between source and epicentre r , r^{/prime} Space coordinates /vec{r}_{0} Centroid position of point-like source R Rise time R_{xx} /left( /tau /right) Auto-correlation function R_{yy} /left( /tau /right) Auto-correlation function R_{xy} /left( /tau /right) Cross-correlation function r_{x} /left( /tau /right) Normalized auto-correlation function r/left( /tau /right) Normalized auto-correlation function of Poisson distribution s_{{/rm f}} Skewness (frequency domain) s_{{/rm x}} Skewness (time domain) S_{1} , S_{2} , S_{3} Individual clusters t Time t , t^{/prime} Time coordinates {/Delta }t Unit time, time interval {/Delta }t_{{/rm s}} Sampling time interval T Displacement threshold T Transducer response u_{i} /left( {r,/,t} /right) Displacement in ith direction depending on space and time coordinates U/left( t /right) Voltage of measured signals at transducer /overline{{U^{2} }} Mean square voltage /overline{{U_{{/rm noise}}^{2} }} Average background noise U_{{/rm p}} Maximum AE amplitude, peak voltage U_{{/rm RMS}} Root mean square voltage U_{{/rm th}} Threshold value for voltage signal U_{z} Maximum displacement in z-direction (surface normal) v Velocity x_{1} , x_{2} , x_{3} Elements of data set X/left( t /right) Random data /hat{X}/left( t /right) Fourier transform of X/left( t /right) /hat{X}_{{/rm T}} /left( t /right) Truncated Fourier transform of X/left( t /right) Y/left( t /right) Random data Z_{{/rm cc}} Correlation coefficient /alpha Significance level /gamma_{{/rm merged}} Centroid drift vector /delta /left( {t - t^{/prime}} /right) Delta function /delta_{{/rm merged}} Inter-cluster distance /mu_{x} Mean value /mu_{x}^{/left( 1 /right)} First moment /mu_{x}^{/left( 2 /right)} Second moment /sigma Source function (time domain) /sigma Pre-existing vertical stress /sigma_{x} Standard deviation /sigma_{x}^{2} Variance (time domain) /sigma_{{/rm f}}^{2} Variance (frequency domain) /tau Inter-event time interval /tau_{0} Relaxation time /chi^{2} Chi-square function {X}^{2} Goodness-of-fit test {/Psi }^{2} /left( t /right) Mean square value 25
Displacement and Strain Fields 28
Temperature Fields 29
Fully-Coupled Measurements 30
High-alloy CrMnNi TRIP/TWIP Steels 31
Case Studies 31
List of Figures 1
List of Tables 1
1 Motivation 34
References 38
2 Plastic Deformation and Strain Localizations 39
Abstract 39
2.1 Plastic Deformation 39
2.2 Dislocation Glide 43
2.3 Deformation Twinning 47
2.4 Critical Resolved Shear Stress 51
2.5 Strain Hardening 53
2.6 Strain Localizations 56
2.6.1 Strain Localizations on Microscopic Scale 59
2.6.1.1 Slip Bands/Deformation Bands 59
2.6.1.2 Persistent Slip Bands 60
2.6.1.3 Shear Bands 63
2.6.2 Strain Localizations on Macroscopic Scale 65
2.6.2.1 Lüders Effect 67
2.6.2.2 Portevin–Le Chatelier Effect 69
References 73
3 Martensitic Phase Transformation 78
Abstract 78
3.1 General Considerations 78
3.2 Thermodynamic Aspects of Martensitic Phase Transformation 81
3.3 Martensite in Ferrous Alloys 83
3.4 Martensitic Phase Transformation in Steels 85
3.4.1 Direct ? to ?? Transformation 86
3.4.2 Direct ? to ? Transformation 91
3.4.3 Direct ? to ?? Transformation 92
3.4.4 Indirect ?–?? Transformation via ?-Martensite 93
3.5 Influence of Stacking-Fault Energy 94
3.6 Olson–Cohen Model of Martensitic Phase Transformation 97
References 99
4 Advanced High-Strength Steels 101
Abstract 101
4.1 General Considerations 101
4.2 Twinning-Induced Plasticity (TWIP) Steels 103
4.2.1 Thermodynamic Aspects of TWIP Steels 103
4.2.2 Deformation Behaviour of TWIP Steels 104
4.2.3 Modelling of the TWIP Effect 110
4.3 Transformation-Induced Plasticity (TRIP) Steels 113
4.3.1 Thermodynamic Aspects of TRIP Steels 114
4.3.2 Deformation Behaviour of TRIP Steels 119
4.3.3 Modelling of the TRIP Effect 124
References 126
5 In Situ Techniques for Characterization of Strain Localizations and Time Sequence of Deformation Processes 129
Abstract 129
5.1 General Considerations 129
5.2 In Situ Imaging Techniques 132
5.2.1 Optical Microscopy 132
5.2.1.1 In Situ Experiments with Optical Microscopy 133
5.2.1.2 State of the Art in Materials Engineering 134
5.2.2 Scanning Electron Microscopy 138
5.2.2.1 In Situ Experiments in Scanning Electron Microscopes 139
5.2.2.2 State of the Art in Materials Engineering 141
5.3 In Situ Acoustic Emission Measurements 145
5.3.1 General Aspects of Acoustic Emission 146
5.3.2 Acoustic Emission—A Multiscale Random Time-Series Process 149
5.3.3 Sources of Acoustic Emission 160
5.3.4 Instrumentation and Data Acquisition 165
5.3.5 Processing of AE Data 170
5.3.6 State of the Art in Materials Engineering 181
5.4 In Situ Full-Field Measurement Techniques 186
5.4.1 Displacement and Strain Fields 187
5.4.1.1 General Aspects of Digital Image Correlation 188
5.4.1.2 Principles of Digital Image Correlation 191
5.4.1.3 Computation of 2D Strain Values 197
5.4.1.4 State of the Art in Materials Engineering 202
5.4.2 Temperature Fields 209
5.4.2.1 General Aspects of Infrared Thermography 210
5.4.2.2 Heat Sources and Dissipated Energy 214
5.4.2.3 State of the Art in Materials Engineering 218
5.4.3 Fully-Coupled Measurements 221
References 225
6 Object of Investigations—High-Alloy Fe–16Cr–6Mn–xNi–0.05C Cast Steels with TRIP/TWIP Effect 234
Abstract 234
6.1 General Considerations on High-Alloy Fe–16Cr–6Mn–xNi–0.05C TRIP/TWIP Steels 234
6.2 Applied Methods for Characterization of the Deformation Behaviour and the Related Microstructures 238
6.2.1 Deformation Experiments 238
6.2.2 Microstructural Characterization Techniques 239
6.3 Mechanical Behaviour 242
6.3.1 Uniaxial Quasi-static Loading 242
6.3.2 Uniaxial Cyclic Loading 246
6.3.3 Planar-Biaxial Loading 248
6.4 Microstructure Evolution 250
6.4.1 Fe–16Cr–6Mn–6Ni–0.05C Steel 250
6.4.2 Fe–16Cr–6Mn–9Ni–0.05C Steel 267
6.4.3 Fe–16Cr–6Mn–3Ni–0.05C Steel 270
References 272
7 Case Studies on Localized Deformation Processes in High-Alloy Fe–16Cr–6Mn–xNi–0.05C Cast Steels 274
Abstract 274
7.1 Significance of Complementary In Situ Characterization Techniques 274
7.2 Microscopic Strain Localizations During Plastic Deformation 278
7.2.1 In Situ Deformation in the Scanning Electron Microscope 278
7.2.2 High-Resolution DIC (Sub-µDIC) for Evaluation of Local Strain Fields 280
7.2.3 Strain Localization During Tensile Deformation 283
7.2.4 Orientation-Dependent Magnitude of Shear of Individual Martensitic Grains 302
7.2.5 Magnitude of Shear of Twin Bundles 306
7.2.6 Strain Localization During Cyclic Deformation 310
7.2.7 Discussion 336
7.3 Time Sequence of Deformation Processes 342
7.3.1 Acoustic Emission Measurements and Analysis 342
7.3.2 Acoustic Emission During the Deformation Process 344
7.3.3 Influence of Chemical Composition 352
7.3.4 Evolution of Martensitic Phase Transformation at Room Temperature 359
7.3.5 Influence of Deformation Temperature 360
7.3.6 Discussion 367
7.4 Macroscopic Strain Localization During Plastic Deformation 369
7.4.1 Fully-Coupled Full-Field Measurements 370
7.4.2 The Occurrence of Portevin–Le Chatelier (PLC) Effect 371
7.4.3 Temperature and Strain Fields 375
7.4.4 Portevin–Le Chatelier Effect and Acoustic Emission 382
7.4.5 Correlation of PLC Effect with Martensitic Volume Fraction 383
7.4.6 Discussion 389
References 392
8 Prospects of Complementary In Situ Techniques 394
Abstract 394
8.1 General Remarks 394
8.2 Complementary In Situ Techniques and Microstructural-Based Modelling 397
8.3 Example 1: Modelling of Strain-Hardening Behaviour of CrMnNi TRIP/TWIP Steels 400
8.3.1 Orientation Dependence of Deformation Mechanisms Detected by AE 403
8.3.2 Strain Localizations Across the Length Scale of Microstructure 404
8.4 Example 2: Damage Behaviour of TRIP Matrix Composites 408
8.5 Example 3: Deformation and Damage Behaviour of Laminated TRIP/TWIP Composites 410
8.6 Example 4: Shape Memory Materials 411
References 412
9 Concluding Remarks 414
Appendix 419
References 420
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References 420
Index 464
488628_1_En_10_Chapter_OnlinePDF.pdf 1
10 Correction to: Deformation Processes in TRIP/TWIP Steels 418
Correction to: A. Weidner, Deformation Processes in TRIP/TWIP Steels, Springer Series in Materials Science 295, https://doi.org/10.1007/978-3-030-37149-4 418