Thermal Expansion of a Multiphase Intermetallic Ti-Al-Nb-Mo Alloy Studied by High-Energy X-ray Diffraction

Intermetallic gamma-TiAl-based alloys are lightweight materials for high-temperature applications, e.g., in the aerospace and automotive industries. They can replace much heavier Ni-based alloys at operating temperatures up to 750 degrees C. Advanced variants of this alloy class enable processing routes that include hot forming. These alloys consist of three relevant crystallographic phases (gamma-TiAl, alpha(2)-Ti3Al, beta(o)-TiAl) that transform into each other at different temperatures. For thermo-mechanical treatments as well as for adjusting alloy properties required under service conditions, the knowledge of the thermal expansion behavior of these phases is important. Therefore, thermal expansion coefficients were determined for the relevant phases in a Ti-Al-Nb-Mo alloy for temperatures up to 1100 degrees C using high-energy X-ray diffraction.

Automated summary

Intermetallic gamma-TiAl-based alloys are lightweight materials suitable for high temperature applications, capable of replacing heavier Ni-based alloys. These alloys consist of three crystallographic phases that transform into each other at different temperatures.