SPS synthesis and consolidation of TiAl alloys from elemental powders: Microstructure evolution

Some works have studied the sintering of TiAl by means of Spark Plasma Sintering (SPS) and it is believed that it is possible to obtain very fine microstructures and very interesting mechanical properties. As raw materials, normally pre-alloyed powders have been used, obtained by atomization or mechanical alloying. However, few works have studied the consolidation of elemental powders. This work presents the synthesis and densification of TiAl-based alloys by means of Spark Plasma Sintering (SPS) using elemental powders as raw materials. The selected composition was Ti–48Al–2Cr–2Nb. The densification process, the evolution of the microstructure with the temperature and the diffusion of the elements (including heavy metals Cr and Nb) are presented. In addition, SPS products are compared with TiAl alloys from elemental powders obtained by conventional methods.

► Study of the SPS process of TiAl, using elemental powders.
► Effect of load in the densification and evolution of microstructure vs temperature.
►  Effect of the holding time in the diffusion of the elements.
► Diffusion of heavy elements (Cr, Nb) by SEM and chemical analysis.
► Comparison of SPS with conventional sintering methods.