Study on the Formation of Nano tau 3 Phase by Mechanical Alloying

In the present investigation the pure elemental powder mixture of Al (70 at%) Ni (15 at %), Cu (15 at %) was mechanically milled in an attritor ball mill for 10, 20, 40, 60, 80 and 100 hours in hexane medium at 400 rpm. The isothermal annealing of 100 h mechanically milled powder has been done at 700 0C for 20, 40 and 60 hours. The mechanically alloyed powders are characterized using X-ray diffraction, differential thermal analysis and transmission electron microscopy techniques. It was observed that mechanical alloying led to the formation of nano tau 3 phases in Al70 Cu15Ni15 after 80 h of milling. In the case of 100 h MM and subsequent annealing at 700 0 C for 20, 40 and 60 h, powder exhibited the formation of tau 3 phases with bigger grain sizes. The phase formation and transformations in the above systems have been discussed based.