After almost three decades of intensive fundamental research and development activities, intermetallic titanium aluminides based on the ordered γ-TiAl phase have found applications in automotive and aircraft engine industry. The advantages of this class of innovative high-temperature materials are their low density and their good strength and creep properties up to 750 °C as well as their good oxidation and burn resistance. Advanced TiAl alloys are complex multi-phase alloys which can be processed by ingot or powder metallurgy as well as precision casting methods. Each process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and/or subsequent heat treatments. The background of these heat treatments is at least twofold, i.e., concurrent increase of ductility at room temperature and creep strength at elevated temperature. This review gives a general survey of engineering γ-TiAl based alloys, but concentrates on β-solidifying γ-TiAl based alloys which show excellent hot-workability and balanced mechanical properties when subjected to adapted heat treatments. The content of this paper comprises alloy design strategies, progress in processing, evolution of microstructure, mechanical properties as well as application-oriented aspects, but also shows how sophisticated ex situ and in situ methods can be employed to establish phase diagrams and to investigate the evolution of the micro- and nanostructure during hot-working and subsequent heat treatments.

Design, Processing, Microstructure, Properties, and Applications of Advanced Intermetallic TiAl Alloys†

Get the phase diagram information you need at a price you can afford. Key Features: Peer reviewed by the Japanese Committee for Alloy Phase Diagrams. Updated through April 2000. Total number of diagrams = 2,332 (605 are new of greatly revised diagrams; among these 171 are not in Binary Alloy Phase Diagrams, 2nd Edition). Approximately 600 crystal structure tables of systems for which phase diagrams are unknown. You've been asking for a simple book containing just binary phase diagrams and crystal structure data. Desk Handbook: Phase Diagrams for Binary Alloys meets this need, and it presents the most current information. Updates the previous print compilation of binary phase diagrams by 10 years. Presents diagrams in consistent size. Shows the principal axis in atomic per cent, with a secondary axis in weight per cent. Includes an introductory article on phase diagrams and their use. Gives reference to the original literature source. This volume is the latest outgrowth of the phase diagram activity in which ASM International has been involved since 1978.

Desk handbook phase diagrams for binary alloys

Advances in gamma titanium aluminides and their manufacturing techniques

The mechanical properties of ex-situ and in-situ metallic glass matrix composites (MGMCs) have proven to be both scientifically unique and of potentially important for practical applications. However, the underlying deformation mechanisms remain to be studied. In this article, we review the development, fabrication, microstructures, and properties of MGMCs, including the room-temperature, cryogenic-temperature, and high-temperature mechanical properties upon quasi-static and dynamic loadings. In parallel, the deformation mechanisms are experimentally and theoretically explored. Moreover, the fatigue, corrosion, and wear behaviors of MGMCs are discussed. Finally, the potential applications and important unresolved issues are identified and discussed.

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Metallic glass matrix composites

Despite the fact that additive manufacturing (AM) techniques allow to manufacture complex porous parts with a controlled architecture, differences can occur between designed and as-produced morphological properties. Therefore this study aimed at optimizing the robustness and controllability of the production of porous Ti6Al4V structures using selective laser melting (SLM) by reducing the mismatch between designed and as-produced morphological and mechanical properties in two runs. In the first run, porous Ti6Al4V structures with different pore sizes were designed, manufactured by SLM, analyzed by microfocus X-ray computed tomography (micro-CT) image analysis and compared to the original design. The comparison was based on the following morphological parameters: pore size, strut thickness, porosity, surface area and structure volume. Integration of the mismatch between designed and measured properties into a second run enabled a decrease of the mismatch. For example, for the average pore size the mismatch decreased from 45% to 5%. The demonstrated protocol is furthermore applicable to other 3D structures, properties and production techniques, powder metallurgy, titanium alloys, porous materials, mechanical characterization, tomography.

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J.P. Lin

Papers

Effect of Nb on oxidation behavior of high Nb containing TiAl alloys

Effects of Nb and Al on the microstructures and mechanical properties of high Nb containing TiAl base alloys

Effect of annealing temperature on magnetic properties of cold rolled high silicon steel thin sheet

Microstructural control of TiAl–Nb alloys by directional solidification

Microstructure and tensile properties of as-cast Ti–45Al–(8–9)Nb–(W, B, Y) alloy