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