The present article will describe aspects of the science and technology of titanium aluminide (TiAl) alloy system and summarise the low and high temperature mechanical and environmental properties exhibited by different alloy generations. In terms of processing developments, conventional gravity casting and near net shape casting would be discussed in detail. Also newer and non-conventional forging and additive manufacturing routes would be briefly highlighted. Extensive investigations of TiAl alloys have enabled their commercial implementation in aerospace and automotive industries. The GEnx™ engine is the first commercial aircraft engine that used TiAl (alloy 48–2–2) for their low pressure turbine blades. Among non GE engines, recently, new β-stabilised TiAl alloy (TNM) is being used to manufacture LPT blades for PW1100G™ engines. TiAl materials and design processes can reduce engine weight and improve engine performance.

TiAl alloys in commercial aircraft engines

An overview of tailoring strain delocalization for strength-ductility synergy

Intermetallic titanium aluminides based on the ordered γ-TiAl phase have gained increasing interest as innovative high-temperature light-weight structural materials. They have found application in aerospace and automotive industries and are still subject of worldwide research and development activities. Their attractive properties perfectly match the engine manufacturers’ demands. This review, bridges the gap from the development of the TNM alloy through structural characterization with sophisticated in and ex situ methods, engineering properties, manufacturing, and processing technologies to all aspects of application. Because one thing is clear, the material still has great potential.

Intermetallic β‐Solidifying γ‐TiAl Based Alloys − From Fundamental Research to Application

Microstructural evolution and high-temperature oxidation mechanisms of a titanium aluminide based alloy

New methods for automatic quantification of microstructural features using digital image processing

Effect of hot rolling and primary annealing on the microstructure and texture of a β-stabilised γ-TiAl based alloy

In-situ study of the time–temperature-transformation behaviour of a multi-phase intermetallic β-stabilised TiAl alloy

Lattice and phase strain evolution during tensile loading of an intermetallic, multi-phase γ-TiAl based alloy

Challenging issues concerning energy efficiency and environmental politics require novel approaches to materials design. A recent example with regard to structural materials is the emergence of lightweight intermetallic TiAl alloys. Their excellent high-temperature mechanical properties, low density and high stiffness constitute a profile perfectly suitable for their application as advanced aero-engine turbine blades or as turbocharger turbine wheels in next-generation automotive engines. As the properties of TiAl alloys during processing as well as during service are dependent on the phases occurring, detailed knowledge of their volume fractions and distribution within the microstructure is of paramount importance. Furthermore, the behavior of the individual phases during hot deformation and subsequent heat treatments is of interest to define reliable and cost-effective industrial production processes. In situ high-energy X-ray diffraction methods allow tracing the evolution of phase fractions over a large temperature range. Neutron diffraction unveils information on order-disorder transformations in TiAl alloys. Small-angle scattering experiments offer insights into the materials’ precipitation behavior. This review attempts to shine a light on selected in situ diffraction and scattering techniques and the ways in which they promoted the development of an advanced engineering TiAl alloy.

In Situ Characterization Techniques Based on Synchrotron Radiation and Neutrons Applied for the Development of an Engineering Intermetallic Titanium Aluminide Alloy

Petra Erdely

Papers

Intermetallic β‐Solidifying γ‐TiAl Based Alloys − From Fundamental Research to Application

Effect of hot rolling and primary annealing on the microstructure and texture of a β-stabilised γ-TiAl based alloy

In-situ study of the time–temperature-transformation behaviour of a multi-phase intermetallic β-stabilised TiAl alloy

Lattice and phase strain evolution during tensile loading of an intermetallic, multi-phase γ-TiAl based alloy

In Situ Characterization Techniques Based on Synchrotron Radiation and Neutrons Applied for the Development of an Engineering Intermetallic Titanium Aluminide Alloy