Gamma Titanium Aluminide Alloys

Fritz Appel has continued to play an active role in TiAl research since his retirement in 2006 as group leader of physical metallurgy. He obtained his Ph.D. in 1973 and his habilitation in 1987 from the Martin-Luther University in Halle, Germany. He spent six months in Japan on a JSPS fellowship in 1987, joining the GKSS Research Center in Geesthacht in 1990. Dr. Appel received the Tammann Award from the German Society for Materials Science in 1999 and the Charles Hatchett Award in 2002 from the Institute of Materials, London. He has published over 160 papers, given over 80 invited lectures and holds six patents in the field. Jonathan Paul has been a member of the Institute of Materials Research in Geesthacht since 1999. He obtained his Ph.D. from Manchester University in 1990, and after a year of postdoctoral research, moved to the Commissariat a l'Energie Atomique at Saclay in 1993. Between 1995 and 1997 he worked as a research fellow at GKSS, before being employed at the Defence Evaluation Research Agency (formerly known as the Royal Aircraft Establishment, now re-named QinetiQ) within the Structural Materials Centre in Farnborough. Dr. Paul received the Vanadium Award in 1995 and the Charles Hatchett Award in 2002, both from the Institute of Materials, London. He has co-authored and authored a number of publications and holds four patents. Michael Oehring works in the physical metallurgy group at the Institute of Materials Research in Geesthacht. He received his Ph.D. in 1988 from the University of Gottingen, Germany, where he remained until 1989, working in the area of field ion microscopy. He then joined the applied physical metallurgy group at GKSS, where he remained until 1993, before transferring to the group headed by Fritz Appel. Dr. Oehring received the Charles Hatchett Award in 2002 from the Institute of Materials, London, and has authored or co-authored over 100 papers as well as five patents.

“To summarize, this book is not only useful as a reference book for industrial users, but also as a textbook for students. It should really not be missing in any university library.”  (Materials and Corrosion, 1 November  2012)

• Preface INTRODUCTION CONSTITUTIONThe Binary Ti-Al Phase DiagramTernary and Multicomponent Alloy Systems THERMOPHYSICAL CONSTANTSElastic and Thermal PropertiesPoint DefectsDiffusion PHASE TRANSFORMATIONS AND MICROSTRUCTURESMicrostructure Formation on SolidificationSolid State Transformations DEFORMATION BEHAVIOR OF SINGLE-PHASE ALLOYSSingle-Phase Gamma(TiAl) AlloysDeformation Behavior of Single-Phase Alpha2(Ti3Al) AlloysBeta/B2 Phase Alloys DEFORMATION BEHAVIOR OF TWO-PHASE ALPHA(Ti3Al) + GAMMA(TiAl) ALLOYSLamellar MicrostructuresDeformation Mechanisms, Contrasting Single-Phase and Two-Phase AlloysGeneration of Dislocations and Mechanical TwinsGlide Resistance and Dislocation MobilityThermal and Athermal Stresses STRENGTHENING MECHANISMSGrain RefinementWork HardeningSolution HardeningPrecipitation HardeningOptimized Nb-Bearing Alloys DEFORMATION BEHAVIOR OF ALLOYS WITH A MODULATED MICROSTRUCTUREModulated MicrostructuresMisfitting InterfacesMechanical Properties CREEPDesign Margins and Failure MechanismsGeneral Creep BehaviorThe Steady-State or Minimum Creep RateEffect of MicrostructurePrimary CreepCreep-Induced Degradation of Lamellar StructuresPrecipitation Effects Associated with the Alpha2 -> Gamma Phase TransformationsTertiary CreepOptimized Alloys, Effect of Alloy Composition and ProcessingCreep Properties of Alloys with a Modulated Microstructure FRACTURE BEHAVIORLength Scales in the Fracture of TiAl AlloysCleavage FractureCrack-Tip PlasticityFracture Toughness, Strength, and DuctilityFracture Behavior of Modulated AlloysRequirements for Ductility and ToughnessAssessment of Property Variability FATIGUEDefinitionsThe Stress-Life (S-N) BehaviorHCFEffects of Temperature and Environment on the Cyclic Crack-Growth ResistanceLCFThermomechanical Fatigue and Creep Relaxation OXIDATION BEHAVIOR AND RELATED ISSUESKinetics and ThermodynamicsGeneral Aspects Concerning OxidationSummary ALLOY DESIGNEffect of Aluminum ContentImportant Alloying Elements -General RemarksSpecific Alloy SystemsSummary INGOT PRODUCTION AND COMPONENT CASTINGIngot ProductionCastingSummary POWDER METALLURGYPrealloyed Powder TechnologyElemental-Powder TechnologyMechanical Alloying WROUGHT PROCESSINGFlow Behavior under Hot-Working ConditionsConversions of MicrostructureWorkabiliy and Primary ProcessingTexture EvolutionSecondary Processing JOININGDiffusion BondingBrazing and Other Joining Technologies SURFACE HARDENINGShot Peening and Roller BurnishingResidual Stresses, Microhardness, and Surface RoughnessSurface Deformation Due to Shot PeeningPhase Transformation, Recrystallization, and AmorphizationEffect of Shot Peening on Fatigue StrengthThermal Stability of the Surface Hardening APPLICATIONS, COMPONENT ASSESSMENT, AND OUTLOOKAerospaceAutomotiveOutlook