Abstract: INTRODUCTION Introduction History of the MAX Phases STRUCTURE, BONDING, AND DEFECTS Introduction Atom Coordinates, Stacking Sequences, and Polymorphic Transformations Lattice Parameters, Bond Lengths, and Interlayer Thicknesses Theoretical Considerations To Be or Not to Be Distortion of Octahedra and Trigonal Prisms Solid Solutions Defects Summary and Conclusions ELASTIC PROPERTIES, RAMAN AND INFRARED SPECTROSCOPY Introduction Elastic Constants Young's Modulus and Shear Modulus Poisson's Ratios Bulk Moduli Extrema in Elastic Properties Effect of Temperature on Elastic Properties Raman Spectroscopy Infrared Spectroscopy Summary and Conclusions THERMAL PROPERTIES Introduction Thermal Conductivities Atomic Displacement Parameters Heat Capacities Thermal Expansion Thermal Stability Summary and Conclusions ELECTRONIC, OPTICAL, AND MAGNETIC PROPERTIES Introduction Electrical Resistivities, Hall Coefficients, and Magnetoresistances Seebeck Coefficients, Theta Optical Properties Magnetic Properties Superconducting Properties Summary and Conclusions OXIDATION AND REACTIVITY WITH OTHER GASES Introduction Ti3SiC2 Tin+1AlXn Solid Solutions between Ti3AlC2 and Ti3SiC2 Cr2AlC Nb2AlC and (Ti0.5,Nb0.5)2AlC Ti2SC V2AlC and (Ti0.5,V0.5)2AlC Ti3GeC2 and Ti3(Si,Ge)C2 Ta2AlC Ti2SnC, Nb2SnC, and Hf2SnC Ti2InC, Zr2InC, (Ti0.5, Hf0.5)2InC, and (Ti0.5,Zr0.5)2InC Sulfur Dioxide, SO2 Anhydrous Hydrofluoric, HF, Gas Chlorine Gas Summary and Conclusions Appendix CHEMICAL REACTIVITY Introduction Diffusivitiy of M and A Atoms Reactions with Si, C, Metals, and Intermetallics Reactions with Molten Salts Reactions with Common Acids and Bases Summary and Conclusions DISLOCATIONS, KINKING NONLINEAR ELASTICITY, AND DAMPING Introduction Dislocations and Their Arrangements Kink Band Formation in Crystalline Solids Incipient Kink Bands Microscale Model for Kinking Nonlinear Elasticity Experimental Verification of the IKB Model Effect of Porosity Experimental Evidence for IKBs Why Microcracking Cannot Explain Kinking Nonlinear Elasticity The Preisach - Mayergoyz Model Damping Nonlinear Dynamic Effects Summary and Conclusions MECHANICAL PROPERTIES: AMBIENT TEMPERATURE Introduction Response of Quasi-Single Crystals to Compressive Loads Response of Polycrystalline Samples to Compressive Stresses Response of Polycrystalline Samples to Shear Stresses Response of Polycrystalline Samples to Flexure Stresses Response of Polycrystalline Samples to Tensile Stresses Hardness Fracture Toughness and R-Curve Behavior Fatigue Resistance Damage Tolerance Micromechanisms Responsible for High K1c, R-Curve Behavior, and Fatigue Response Thermal Sock Resistance Strain Rate Effects Solid Solution Hardening and Softeing Machinability Summary and Conclusions MECHANICAL PROPERTIES: HIGH TEMPERATURES Introduction Plastic Anisotropy, Internal Stresses, and Deformation Mechanisms Creep Response to Other Stress States Summary and Conclusions EPILOGUE Outstanding Scientific Questions MAX Phase Potential Applications Forming Processes and Sintering Outstanding Technological Issues Some Final Comments INDEX