A Process for Production of a Niobium-containing TiAl Based Alloy

作者：Kamali A R^*; Hadi M; Khalil Allafi J; Ebrahimi A R

来源：Canadian Metallurgical Quarterly, 2010, 49(2): 171-178.

• Titanium aluminide
• Chemical composition
• Homogenization
• Microstructure

A new generation of turbine engines based on titanium aluminides may be commercially manufactured if these materials could be produced more cheaply and more easily. In the present work, challenges faced during the production of a gamma-TiAl-based alloy (Ti-48Al-2Cr-2Nb-1B (at%) including the evaporation of aluminum and the formation of niobium-rich inclusions were studied and a set of recommendations has been proposed to overcome them. It was found that TiAl and Nb3Al are appropriate master alloys to produce an alloy with a controllable chemical composition and a microstructure free from inclusions without a need for any extra melting processes. A two stage mechanism was found to be responsible for chemical composition variation during the production of the alloy using elemental raw materials: a sharp aluminum loss in the first melting and a moderate one in the second and third melting processes. The first stage can be avoided by using master alloys.
It was demonstrated that mechanical properties of an alloy produced after an appropriate heat treatment is comparable to alloys produced by other methods. Prevention of extra melting times has a strong impact on economics and commercialization of these materials.

• 出版日期2010-4