Effect of Si on Nanostructured TiAl Intermetallic Compound Formation Kinetic by MA Method

Intermetallic titanium aluminides, particularly TiAl (γ) based alloys, have received a great deal of attention as candidate materials for high-temperature applications such as aerospace and automobile industries because of their low density, high specific strength. However the poor ductility and fracture toughness at ambient to intermediate temperatures are the major obstacles for practical use of these materials [1]. Attempts adupted include techniques such as grain refinement to nano scale structure [2] and microstructure modification. Mechanical alloying process has been shown to be an effective means to achieve grain refinement.It has also been found that addition of some s such as Nb, V, Cr and Si improves the high temperature properties of TiAl based alloys. Si appeared to be an attractive ternary element candidate which raises the creep resistance of the alloy due to ζ-Ti5Si3 phase formation as the strengthening constituent [3].In the present work, the compositional Ti-50Al and Ti-48Al-2.4Si powder blends were used to perform MA process. The study aimed to investigate the structural evaluation of the powders during MA process and also after annealing treatments of mechanically milled powders