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

摘要

Challenging issues concerning energy efficiency and environmental politics requirenovel approaches to materials design. A recent example with regard to structural materials isthe emergence of lightweight intermetallic TiAl alloys. Their excellent high-temperature mechanicalproperties, low density and high stiffness constitute a profile perfectly suitable for their applicationas advanced aero-engine turbine blades or as turbocharger turbine wheels in next-generationautomotive engines. As the properties of TiAl alloys during processing as well as during service aredependent on the phases occurring, detailed knowledge of their volume fractions and distributionwithin the microstructure is of paramount importance. Furthermore, the behavior of the individualphases during hot deformation and subsequent heat treatments is of interest to define reliable andcost-effective industrial production processes. In situ high-energy X-ray diffraction methods allowtracing the evolution of phase fractions over a large temperature range. Neutron diffraction unveilsinformation on order-disorder transformations in TiAl alloys. Small-angle scattering experimentsoffer insights into the materials’ precipitation behavior. This review attempts to shine a light onselected in situ diffraction and scattering techniques and the ways in which they promoted thedevelopment of an advanced engineering TiAl alloy.