The refining process and solubility of Ti in Al matrix during mechanical alloying (MA) were investigated by using X-ray diffraction (XRD), transmission electron microscopy (TEM) as functions of alloy composition, milling time and ball to powder ratio (BPR). Mechanical alloyed samples were annealed for investigating their stability and the formation behavior of Al 3 Ti in the temperature range from 200?C to 600?C . It is observed from present experimental that disappearance of Ti peaks in mechanically alloyed Al-10wt%Ti is not simply attributable to the dissolution of Ti into Al, but associated mainly with extreme refining and/or heavy straining of Ti particles The annealing of the mechanically alloyed Al-Ti powders show differences in aluminide formation behavior when Ti content in Al is equal to or less than l0wt% and higher than l5wt%Ti. When Ti-content in Al is equal to or less than l0wt%, the MA powders transform directly to a global equilibrium state forming DO 22 ?typeAl 3 Ti above 400?C . In the Al-Ti samples with equal to or higher than l5wt%Ti, transitional phases of cubic Al 3 Ti and tetragonal Al 24 Ti 8 are formed above 400?C . They are stable only below 500?C , and, DO 22 ?typeAl 3 Ti becomes dominant aluminide at temperature higher than 600oC .