Fabrication of TiAl alloys by alternative powder methods

Until now TiAl alloys have been produced using a variety of processing methods including forging, extrusion, casting, etc. One important problem is the variation in mechanical properties caused by the segregation in the composition. In order to improve these segregations, powder metallurgy is an interesting alternative for the processing of TiAl alloys. However, some drawbacks of PM have limited the practical application of TiAl alloys such as the costs of the pre-alloyed raw materials, the use of expensive processing methods like HIP, etc. This work presents the activities performed at Tecnalia in the development of novel cost effective PM processing routes. Processes like Spark Plasma Sintering and Combustion Synthesis will be presented. Microstructures, crystallographic phases, chemical analysis and mechanical properties (tensile and creep) of the different processing routes will be detailed. Main advantages of these methods are the short processing time and the possibility of using elemental powders.