Introduction to Low Pressure Gas Dynamic Spray: Physics & Technology

Introduction to Low Pressure Gas Dynamic Spray......Page 5
Contents......Page 7
Preface......Page 13
1.1 General Description......Page 15
1.2.1 Coating Characterization......Page 18
1.2.2 Flame Spraying......Page 19
1.2.4 Plasma Spraying......Page 20
1.2.5 Rapid Prototyping......Page 21
1.2.6 Plasma Deposition Manufacturing......Page 22
1.2.7 Explosive Cladding......Page 23
1.3 Concluding Remarks......Page 24
2.1.1 Main Features......Page 25
2.1.2 Rebound and Erosion Processes......Page 26
2.1.3 GDS Processes......Page 30
2.2.1 Shear Localization Phenomenon......Page 31
2.2.2 Adiabatic Shear Instability in GDS......Page 36
2.2.3 Experiments Relating to Particle Impact......Page 43
2.3 Concluding Remarks......Page 49
3.1 Identification of Various Phenomena......Page 51
3.2 Observations of GDS Consolidated Materials......Page 54
3.3.1 Plastic Deformation Energy......Page 59
3.3.2 Microkinetic Energy......Page 60
3.3.3 Frictional Energy......Page 61
3.3.4 Adiabatic Shear Band Formation Energy......Page 62
3.4 Computation of ASB Energy Parameters......Page 63
3.5 Shear Localization During Particle Shock Consolidation......Page 64
3.6 Impact Powder Compaction Model......Page 65
3.7.1 Constitutive Function......Page 68
3.7.2 Yield Function and Property Estimations......Page 69
3.8 Consolidation Parameters of GDS and Shear Compression......Page 70
3.8.1.2 Shear Compaction Modeling......Page 71
3.9.1 ASB Width Evaluation......Page 72
3.9.2 Yield Stress of Powder Material......Page 73
3.10 Concluding Remarks......Page 74
4.1 State-of-the-Art Cold Spray Systems......Page 79
4.2 State-of-the-Art Powder Feeding Systems......Page 84
4.3 Modification of the Low-Pressure Portable GDS System......Page 87
4.4 An Industrial Low-Pressure Portable GDS System......Page 91
5.1 Statement of Problem......Page 93
5.2 Experimental Procedure......Page 94
5.3 Experimental Results......Page 97
5.3.1 Deposition Efficiency......Page 98
5.3.2 The Effect of the Particle Mass Flow Rate......Page 100
5.3.3 The Build-up Parameter......Page 101
5.3.4 Structure and Properties......Page 102
5.4 Basic Mechanisms......Page 105
5.5 Concluding Remarks......Page 108
6.1 General Relationships......Page 109
6.1.1 The Governing Equations of Single-Phase Turbulent Flow......Page 111
6.1.3 Particle Dynamics in Gas Flow......Page 112
6.2 Gas Flow and Particle Acceleration......Page 114
6.2.1 Computational Fluid Dynamics (CFD)......Page 116
6.2.2 An Engineering Model with Particle Friction......Page 119
6.3.1 Simulation of Gas-Particle Flow in the Nozzle......Page 122
6.3.2 Influence of Gas Pressure......Page 125
6.3.3 Effects of Particle Concentration......Page 126
6.3.4 Effects of Nozzle Wall Friction......Page 128
6.4.1 Shock Wave Features of the Jet......Page 130
6.4.2 An Engineering Model of the Free Jet......Page 133
6.4.3 Particle Flow Structure Within the Normal Shock Region......Page 135
6.4.4 Particle Collisions......Page 137
6.5 Concluding Remarks......Page 138
7.1.2 Gas Flow......Page 139
7.1.4 Deposition Efficiency......Page 141
7.2 Calculations and Discussion......Page 142
7.3 Critical Velocity Evaluation on the Basis of Rebound and Adhesion Phenomena......Page 145
7.4 Concluding Remarks......Page 146
8.1 General Remarks......Page 149
8.2.1.2 Interparticle Bonding......Page 150
8.2.2 Overview of GDS Materials......Page 152
8.2.3 Definition of Structure Parameters......Page 154
8.3.1.1 Strength Tests......Page 156
8.3.1.3 Preparation of Samples......Page 158
8.3.2.2 Rule of Mixture (ROM) Bounds......Page 161
8.3.2.4 Effect of Porosity on Elastic Constants......Page 162
8.3.2.5 Development of MCA Model for GDS Process......Page 164
8.3.2.6 Elastic Modulus and Microstructure of LPGDS Composites......Page 167
8.3.3.1 Strengthening GDS composites......Page 172
8.3.4 Failure Criterion and Microstructural Aspects of Crack Propagation......Page 179
8.3.4.1 Analysis of LPGDS Composite Fracture Characteristics......Page 180
8.4.1 General Analysis and Effects of Residual Stresses......Page 185
8.4.2 Microstructure Analysis of Interface......Page 187
9.1 General Analysis......Page 195
9.2 Repair Applications of GDS Technology......Page 199
9.2.1 LPGDS Composite Coatings for Mechanical Components......Page 200
9.2.2 LPGDS Technology Characterization and Experimental Procedure......Page 201
9.2.3.2 Sliding Wear Behavior......Page 203
9.2.3.3 Analysis of Worn Surfaces......Page 206
9.2.3.5 Wear Process......Page 208
9.2.4 Casting Repair......Page 209
9.2.5 Casting Die Components Repair......Page 210
9.3.1 General Remarks......Page 212
9.3.2.1 Deposition Efficiency......Page 214
9.3.2.2 Microhardness and Microscratching......Page 216
9.4.1 General Remarks......Page 220
9.4.2 Examination of Al–Zn-based Sacrificial Coatings......Page 221
9.5.1 General Remarks......Page 224
9.5.2 Technology Description......Page 225
9.5.3 Results and Discussion......Page 228
9.6 Concluding Remarks......Page 231
Bibliography......Page 233
Index
......Page 245