Hang Z. Yu & Nihan Tuncer 
Solid-State Metal Additive Manufacturing [EPUB ebook] 
Physics, Processes, Mechanical Properties, and Applications

Preface xiii

Part I Introduction 1

1 Introduction and Overview 3
Hang Z. Yu, Nihan Tuncer, and Zhili Feng

1.1 Overview and History of Metal Additive Manufacturing 4

1.2 Liquid-State Bonding Versus Solid-State Bonding 7

1.2.1 Liquid-State Bonding 7

1.2.2 Solid-State Bonding 8

1.3 Nonbeam-Based, Solid-State Metal Additive Manufacturing 9

1.3.1 Deformation-Based Metal Additive Manufacturing 9

1.3.2 Sintering-Based Metal Additive Manufacturing 11

1.4 Additive Manufacturing Categorization Based on the Relationship Between Shape Forming and Consolidation 12

1.5 Organization of the Book 14

References 15

Part II Cold Spray Additive Manufacturing 19

2 Impact-Induced Bonding: Physical Processes and Bonding Mechanisms 21
David Veysset and Mostafa Hassani

2.1 Introduction 21

2.2 Fundamentals of Impact Bonding 23

2.2.1 Plate Impacts and Explosive Welding 23

2.2.1.1 The Shock Equations of State 23

2.2.1.2 Limiting Conditions for Explosive Welding 24

2.2.2 Laser Impact Bonding 30

2.3 Bonding Mechanisms in Cold Spray 32

2.3.1 Proposed Mechanisms 32

2.3.1.1 The Role of Jetting and Impact Pressure in Particle Bonding 32

2.3.1.2 The Limiting Case of Impact Melting 33

2.3.1.3 Adiabatic Shear Instability 36

2.3.1.4 Dissimilar Materials Impact 40

2.3.2 Influence of Particle Characteristics 41

2.3.2.1 Particle Temperature 41

2.3.2.2 Particle Size 42

2.3.2.3 Surface Oxide and Hydroxide Effects 42

References 43

3 Microstructures and Microstructural Evolution in Cold-Sprayed Materials 49
Luke N. Brewer and Lorena I. Perez-Andrade

3.1 Introduction 49

3.2 Defect Structures 50

3.2.1 Vacancies 51

3.2.2 Dislocation Structure 52

3.2.3 Grain Structure 55

3.2.4 Precipitate Structure 56

3.2.5 Porosity 60

3.3 Microstructural Evolution of Thermally Treated Cold-Sprayed Materials 61

3.3.1 Recovery, Recrystallization, and Grain Growth 62

3.3.2 Precipitation 65

3.3.3 Heat Treatment of Feedstock Powders and its Impact on Microstructure 66

3.4 Conclusions 67

Acknowledgements 67

References 68

4 Mechanical Properties of Cold Spray Deposits 75
Sara Bagherifard and Mario Guagliano

4.1 Introduction 75

4.2 Mechanical Properties 76

4.2.1 Adhesive Strength 77

4.2.1.1 Adhesive Strength Test Methods 77

4.2.1.2 The Effect of Process Parameters on Adhesive Strength 80

4.2.1.3 The effect of Pre-/Post-treatments on Adhesive Strength 80

4.2.2 Cohesive Strength 83

4.2.2.1 Cohesive Strength Test methods 84

4.2.2.2 Cohesive Strength Under Static Loading 84

4.2.2.3 Cohesive Strength Under Fatigue Loading 86

4.2.2.4 Anisotropy in Cohesive Strength 90

4.2.3 Summary and Future Perspectives 91

References 94

5 Cold Spray in Practical and Potential Applications 101
Jingjie Wei, Yong He, Phuong Vo, and Yu Zou

5.1 Introduction 101

5.1.1 The Cold Spray Process 101

5.1.2 Cold Spray Additive Manufacturing (CSAM) 103

5.2 Materials 103

5.2.1 Cu and Cu Alloys 103

5.2.1.1 2Cu–Ga and Cu–In–Ga 107

5.2.1.2 Cu–Sn 107

5.2.1.3 Cu–W 107

5.2.2 Al and Al Alloys 108

5.2.3 Ni and Ni Alloys 110

5.2.4 Stainless Steels 111

5.2.5 Body Center Cubic (BCC) Metals 112

5.2.5.1 Tantalum 112

5.2.5.2 Niobium 114

5.2.6 Hexagonal Close-Packed (HCP) Metals 114

5.2.6.1 Titanium 114

5.2.6.2 Magnesium 116

5.2.7 Metal Mixes and Metal Matrix Composite (MMC) 116

5.2.7.1 Metal Mixes 117

5.2.7.2 Metal Matrix Composite 117

5.2.8 Multicomponent and High Entropy Alloys 120

5.2.8.1 MCr Al Y Multicomponent Alloy 120

5.2.8.2 High Entropy Alloy (HEA) 120

5.2.9 Multimaterials 121

5.3 Perspective and Challenges 122

References 124

Part III Additive Friction Stir Deposition 133

6 Process Fundamentals of Additive Friction Stir Deposition 135
David Garcia and Hang Z. Yu

6.1 Additive Friction Stir Deposition – Macroscopic Process Overview 136

6.2 Thermo-Mechanical Processing Evolution 139

6.3 Heat Generation and Heat Transfer 142

6.3.1 Heat Generation and Heat Transfer Mechanisms 142

6.3.2 Peak Temperature and Material Dependence 143

6.4 Material Flow and Deformation 146

References 149

7 Dynamic Microstructure Evolution in Additive Friction Stir Deposition 153
Robert J. Griffiths and Hunter A. Rauch

7.1 Introduction to Microstructure Evolution in Additive Friction Stir Deposition 154

7.2 Dynamic Microstructure Evolution in Single-Phase Materials 155

7.2.1 Stacking Fault Energy and Dislocation Mobility 155

7.2.2 Dynamic Recovery 157

7.2.3 Continuous Dynamic Recrystallization 157

7.2.4 Discontinuous Dynamic Recrystallization 159

7.2.5 Static and Post-Dynamic Recrystallization 160

7.2.6 Heterogeneous Deposits and Metadynamic Recrystallization 161

7.3 Dynamic Microstructure Evolution in Multiple-Phase Materials 162

7.3.1 Thermal Evolution During Additive Friction Stir Deposition 162

7.3.2 Evolution of Secondary Phases at Low Temperature 164

7.3.3 Evolution of Secondary Phases at High Temperature 166

7.3.4 Evolution of Secondary Phases After Deformation 168

7.3.5 Mapping Secondary Phase Evolution to Processing Space 168

7.4 Effects of Material Transport on Microstructure Evolution 170

7.4.1 Mechanisms of Material Transport 170

7.4.2 Material Transport for the Homogenization of Mixtures 172

7.4.3 Densification of Material Through Material Transport 173

7.4.4 Material Transport and Spatial Variance in Thermomechanical Conditions 174

7.5 The Study of Microstructure Evolution in Additive Friction Stir Deposition 175

7.5.1 Contemporary Approaches 175

7.5.2 Novel Approaches 177

Acknowledgement 177

References 177

8 Mechanical Properties of Additive Friction Stir Deposits 181
Dustin Avery and Mackenzie Perry

8.1 Introduction 181

8.2 Magnesium-Based Alloys 184

8.2.1 WE43 184

8.2.2 AZ31 187

8.3 Aluminum-Based Alloys 189

8.3.1 5xxx 190

8.3.2 2xxx 192

8.3.3 6xxx 193

8.3.4 7xxx 195

8.3.5 Cast Al Alloys 197

8.4 Other Alloys Systems 197

8.4.1 Nickel-Based Alloys 197

8.4.2 Copper-Based Alloys 198

8.4.3 Titanium-Based Alloys 198

8.4.4 Steel Alloys 199

8.4.5 High-Entropy Alloys 199

8.4.6 Metal Matrix Composites 200

8.5 Repair 200

8.6 Summary and Future Perspectives 201

8.6.1 Anisotropy 201

8.6.2 Graphite Lubricant 202

8.6.3 Multimaterial or Designed Feedstock 202

8.6.4 Effect of Process Parameters on Mechanical Properties 202

8.6.5 Active Cooling/Heating 202

8.6.6 Heat Treatment 202

8.6.7 High-Temperature Materials – Tool Wear 203

8.6.8 Unique Possibilities 203

8.6.9 Modeling 203

References 203

9 Potential Industrial Applications of Additive Friction Stir Deposition 209
Hang Z. Yu, Rajiv S. Mishra, Chase D. Cox, and Zhili Feng

9.1 Large-Scale Metal Additive Manufacturing 209

9.2 Selective Area Cladding 211

9.3 Recycling and Upcycling 214

9.4 Structural Repair 220

9.5 Underwater Deposition 224

Acknowledgment 227

References 227

Part IV Ultrasonic Additive Manufacturing 231

10 Process Fundamentals of Ultrasonic Additive Manufacturing 233
Austin Ward

10.1 Process Overview 233

10.1.1 Process Parameters 234

10.2 Temperature Rise and Thermal Modeling 235

10.2.1 Heat Generation During Welding 235

10.2.2 Sonotrode Contact Stress 237

10.2.3 Coefficient of Friction 238

10.2.4 Temperature Profile 239

10.3 Feedstock Bonding Mechanisms 241

10.3.1 Oxide Breakdown 241

10.3.2 Asperity Deformation 243

10.3.3 Diffusional Bonding Processes 246

10.3.4 Liquid-Phase Bonding 247

10.4 Dissimilar Metal Consolidation 247

10.4.1 Mechanical and Thermal Modeling 247

10.4.2 Dissimilar Metal Junction Growth 248

10.4.3 Interdiffusion 249

10.5 Acoustic Softening and Strain Normality 251

10.5.1 Cyclic Strain Ratcheting 253

10.6 Summary 254

Acknowledgments 255

References 255

11 Ultrasonic Additive Manufacturing: Microstructural and Mechanical Characterization 259
Tianyang (Tyler) Han, Leon M. Headings, and Marcelo J. Dapino

11.1 Introduction 259

11.2 Microstructure Analysis of UAM Builds 259

11.2.1 Similar Material Joining with UAM 260

11.2.2 Dissimilar Material Joining with UAM 262

11.2.2.1 Al-Ceramic Weld 262

11.2.2.2 Ni-Steel Weld 263

11.3 Hardness Analysis of UAM Builds 266

11.4 Mechanical Characterization of UAM Builds 267

11.4.1 Design of a Custom Shear Testing Method 268

11.4.2 Validation of the Shear Test 268

11.4.3 Finite element Modeling of the Shear Test 270

11.4.4 Application of the Shear Test to UAM Samples 273

11.5 Conclusions 275

References 275

12 Industrial Applications of Ultrasonic Additive Manufacturing 279
Mark Norfolk

12.1 Early Years 279

12.2 Increased Power → Increased Capability 281

12.3 Modern Applications 282

12.3.1 Electrification 282

12.3.2 Thermal Management 286

12.3.3 Embedded Electronics 288

12.3.3.1 Smart Plate 290

12.3.3.2 Sense Pipe 291

12.4 Future Applications 292

References 292

Part V Sintering-Based Processes 295

13 Principles of Solid-State Sintering 297
Basil J. Paudel, Albert C. To, and Amir Mostafaei

13.1 Introduction 297

13.2 Basic Terminology 298

13.2.1 Sintering 298

13.2.2 Relative Density/Green Density 299

13.2.3 Coordination Number 299

13.2.4 Surface Tension/Surface Energy 300

13.2.5 Wetting Angle/Dihedral Angle 300

13.2.6 Neck Growth/Shrinkage/Densification 301

13.3 Sintering Stress 302

13.3.1 Two Particle Model 302

13.3.1.1 Case I: Without Shrinkage 303

13.3.1.2 Case II: With Shrinkage 303

13.3.2 Driving Force 303

13.3.3 Interfacial Activity/Thermodynamics 304

13.4 Mass Transport Mechanisms 306

13.4.1 Grain Boundary Diffusion 306

13.4.2 Lattice/Volume Diffusion 306

13.4.3 Viscous Flow 306

13.4.4 Surface Diffusion 307

13.4.5 Evaporation/Condensation 307

13.4.6 Gas Diffusion 307

13.5 Sintering Stages 307

13.6 Sintering Simulation 308

13.7 Concluding Remarks, Challenges, and Future Works 309

References 310

14 Material Extrusion Additive Manufacturing 313
Alexander C. Barbati and Aaron Preston

14.1 Introduction 313

14.2 Hierarchy of MEAM Parts and Feedstock Behavior 316

14.3 Feedstock Attributes 325

14.4 Extrusion Control 327

14.5 Toolpathing: Strength and Quality 331

14.6 Conclusions 335

Acknowledgments 336

References 336

15 Binder Jetting-based Metal Printing 339
Marco Mariani, Nora Lecis, and Amir Mostafaei

15.1 Introduction to Binder Jetting 339

15.2 Printing Phase 341

15.2.1 Particulate Feedstock 341

15.2.1.1 Feedstock Materials 342

15.2.1.2 Feedstock Morphology and Size Distribution 343

15.2.2 Binder Selection 344

15.2.3 Powder Spreading and Binder Deposition System Configurations 345

15.3 Thermal Treatments 346

15.3.1 Curing 346

15.3.2 Debinding 347

15.3.3 Sintering 348

15.3.4 Additional Treatments 349

15.4 Future Developments 350

15.5 Conclusion 352

References 352

16 Sintering-based Metal Additive Manufacturing Methods for Magnetic Materials 361
H. Wang, A. M. Elliot, and M. P. Paranthaman

16.1 Introduction 361

16.2 Background 362

16.3 Additive Manufacturing Methods 369

16.4 Applications 372

16.5 Summary 374

Acknowledgments 375

References 375

17 Future Perspectives 379
Hang Z. Yu, Nihan Tuncer, and Zhili Feng

17.1 Enhancing the Understanding of Process Fundamentals 379

17.2 Expanding the Printable Material Library 381

17.3 Embracing Artificial Intelligence for Quality Control and Process Prediction 381

References 383

Index 385

Hang Z. Yu, Ph D, is an Associate Professor in the Department of Materials Science and Engineering at Virginia Tech, USA. His research focuses on materials processing and manufacturing science, emphasizing the underlying process physics, mechanics, and kinetics. His work also aims to leverage the process fundamentals to drive material sustainability to new heights, e.g., via solid-state metal recycling, structural repair, and austere condition-resilient manufacturing.
Nihan Tuncer, Ph D, is a Principal Scientist at Desktop Metal Inc. since 2016, where she has been developing solid-state 3D printing technologies and equipment. She holds several patents in addition to research papers and review articles. Her expertise includes powder metallurgy, processing-microstructure-property relationships in ferrous and non-ferrous alloys, porous metals, and shape memory alloys.
Zhili Feng, Ph D, currently leads the Materials Joining Group and is a Distinguished R&D Staff Member of Oak Ridge National Laboratory, USA. His research covers various aspects of thermal-mechanical-metallurgical behaviors of materials in materials joining.