Introduction to metal matrix composites : fabrication and recycling

1 Introduction . . 1
1.1 Classification and Characteristics of Composites . . 2
1.1.1 Classification of Composites . . 2
1.1.2 Characteristics of Metal Matrix Composites . . 3
1.1.3 Examples of Metal Matrix Composite Products . . 4
1.2 Rule of Mixtures . . 9
1.3 Surface Energy and Interface Energy . . 11
1.4 Thermodynamics on Surfaces . . 16
1.5 Wettability . . 19
1.6 Darcy's Law . . 23
References . . 25

2 Fabrication Processes for Composites . . 27
2.1 Aspects of Fabrication of Composites . . 27
2.1.1 Energy of Fabrication . . 27
2.1.2 Fabrication of Composites by Mechanical Methods . . 31
2.1.3 Mechanical Work and Wetting . . 32
2.2 Classification of Fabrication Methods . . 34
2.3 Comparison of Fabrication Techniques . . 34
2.4 Solid State Fabrication . . 35
2.4.1 Powder Metallurgical Methods . . 35
2.4.2 Mechanical Alloying . . 38
2.4.3 Diffusion Bonding . . 39
2.4.4 Spark Plasma Sintering (SPS) . . 40
2.5 Liquid State Fabrication . . 41
2.5.1 Vortex Addition Technique . . 41
2.5.2 Compo-Casting . . 43
2.5.3 Pressureless Infiltration Process . . 44
2.5.4 Ultrasonic Infiltration . . 45
2.6 Gaseous State Fabrication . . 46
2.6.1 CVD . . 46
2.6.2 PVD . . 47
2.7 In Situ Fabrication Process . . 48
2.7.1 Internal Oxidation Process . . 48
2.7.2 Unidirectional Solidification Process . . 49
References . . 50

3 Fabrication by Squeeze Casting . . 53
3.1 Application of Pressure and Fabrication Energy . . 54
3.2 Threshold Pressure . . 56
3.2.1 Case of Random Reinforcement Distribution . . 56
3.2.2 Case of Unidirectional Fiber Distribution . . 57
3.2.3 Measurement of Threshold Pressure . . 58
3.3 Influence of Preheating of Preform . . 58
3.4 Microscopic Analysis of Fluid Flow in Preforms . . 61
References . . 64

4 Theory of Pressure Infiltration . . 67
4.1 Macroscopic Analysis of Fluid Flow in Preforms . . 67
4.1.1 Analysis on the Assumption of Constant Preform Surface Pressure . . 68
4.1.2 Infiltration Velocity Model . . 72
4.2 Infiltration Stop Mechanism . . 88
4.3 Characteristics of Pressure Infiltration Method and Products . . 89
References . . 89

5 Centrifugal Casting of Metal Matrix Composites . . 91
5.1 Infiltration of Molten Metal Using Centrifugal Force . . 91
5.1.1 Pressure Generated at the Surface of Preform . . 92
5.1.2 Infiltration Start Pressure . . 95
5.1.3 Infiltration of Molten Metal into the Preform . . 95
5.1.4 Example Calculations . . 100
5.1.5 Examples of Composites Fabricated Using Centrifugal Force . . 105
5.2 Centrifugal Casting of Particle Dispersed Molten Metal . . 108
References . . 111

6 Properties of Composites . . 113
6.1 Mechanical Properties . . 114
6.1.1 Elastic Modulus . . 114
6.1.2 Strength of Composites . . 120
6.1.3 Fracture of Composites . . 130
6.2 Physical Properties . . 138
6.2.1 Density . . 138
6.2.2 Specific Heat . . 139
6.2.3 Thermal Conductivity . . 140
6.2.4 Thermal Expansion Coefficient . . 142
6.3 Interface . . 147
6.4 New Trends in MMCs . . 148
6.4.1 Carbon/Metal Composites with High Thermal Conductivity . . 148
6.4.2 Smart Composites . . 149
References . . 150

7 Superplasticity of Composites . . 155
7.1 Background for Superplasticity . . 155
7.2 Mechanism of Superplastic Forming . . 156
7.2.1 Superplastic Deformation Mechanism of Alloys . . 157
7.2.2 Superplastic Deformation Mechanism of Composites . . 158
7.3 Production Methods of Superplastic Materials . . 159
References . . 163

8 Materials for the Fabrication of Composites . . 165
8.1 Characteristics of Reinforcements and Matrix Metals . . 166
8.2 Production Processes for Reinforcements . . 168
8.2.1 Ceramic Particles . . 168
8.2.2 Ceramic Fibers and Carbon Fibers . . 169
8.2.3 Ceramic Whiskers . . 175
References . . 178

9 Recycling of Composites . . 181
9.1 Composite Ratio in Products and Re-melting . . 182
9.2 Separation of Fibers or Particles . . 183
9.2.1 State of Composites . . 183
9.2.2 Mechanical Separation of Reinforcements . . 186
9.2.3 Chemical Separation of Reinforcements . . 187
9.3 Separation of Fiber and Metal from Composites . . 189
9.3.1 Chemical Method and Ratio of Separation . . 189
9.3.2 Phenomena Associated with Separation Using Fluxes . . 192
9.4 Entropy of Mixing by the Addition of Reinforcement Particles . . 194
9.4.1 Entropy of Mixing . . 195
9.4.2 Entropy Increase upon the Addition of Particles . . 195
9.5 Assessment of Metal Matrix Composites . . 199
References . . 200

Index . . 201