Characterization of Ti-50%Al composite powder synthesized by high energy ball milling

The Ti-50%Al (molar fraction) composite powder was synthesized by high energy ball milling (HEBM). The characteristics of the composite particles, including surface morphology, structure and components, were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution electron microscopy (HREM) and high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The mechanochemical reaction between Ti and Al gradually took place through intermediate stages during milling, and resulted in the formation of disordered Ti/Al phases. Dissolution of Al in Ti (after 9 h milling), nanocrystalline Ti/Al solid solution and high density of dislocations were caused by HEBM. The element distribution of the mechanically alloyed Ti-50%Al composite powder was close to the initial composition, but the distribution was inhomogeneous.