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. 2021 Aug 30;14(17):4929. doi: 10.3390/ma14174929
Table of Contents
1. Introduction: Metal Additive Manufacturing (AM) Technologies 2
1.1 Fusion-Based AM Techniques 2
1.2. Solid-State AM Techniques 4
1.3. Mixed-Phase (Solid–Liquid) AM Techniques 5
1.4. Surface Engineering via AM Techniques 6
1.5. Comparison and Significance of AM versus Conventional Manufacturing 7
2. Electron-Based Characterization and Diagnostics 8
2.1 Electron Beam-Based Diagnosis/Characterization 8
2.2. X-ray-Based Diagnosis/Characterization 10
2.3. Electron–X-ray Combined Characterization Techniques 10
3. Thermal Imaging 13
3.1. Two-Wavelength Thermal Imaging under the Grey Body Approximation 13
3.2. When the Grey Body Approximation Fails 15
3.3. Discussion on Thermal Imaging 16
4. Ultrasonic Inspection and Evaluation 17
4.1. Ultrasonic Diagnostics 17
4.2. Non-Destructive Ultrasonic Elasticity Measurement and Elastography 24
4.3. Longitudinal and Transversal Sound Velocity Elasticity Measurement 25
4.4. Comparison of Various Ultrasonic Techniques 29
5. Mechanical Test 30
5.1. Elasticity Test with Information on Plasticity 30
5.2. Mechanical Test Provides Only Plasticity 35
5.3. Impact Test 37
5.4. Fatigue Test 38
5.5. Advantages and Disadvantages, Comparison and Discussion of Mechanical Testing 39
6. Laser-Induced Breakdown Spectroscopy 39
7. Other Diagnostic Methods 41
8. Conclusions and Discussion 42
Reference 43