Thermal stability of W-Ni-Fe nano structured and amorphous materials by mechanical alloying

80.7W-13.2Ni-6.1Fe (at.%) tungsten heavy alloys with the structure of amorphous imbedded with residual nano-crystalline W from the elemental powders of W, Ni and Fe have been synthesized by mechanical alloying (MA). Phase transformation and thermal stability of 80.7W-13.2Ni-6.1Fe (at.%) powders milled for 20 h and 60 h were investigated by means of XRD, DTA and DSC. Results show that the different phase transformations occur in the powders milled for 20 h and 60 h during the heating process. For the powders milled for 60 h, besides the relaxation of crystal defaults and lattice stress, the crystallization of amorphous and the precipitation of Ni W phase were both evident during the annealing. Both the primary melting points of the 80.7W-13.2Ni-6.1Fe alloys milled for 20 h and for 60 h decreased by above 200°C, compared with the un-milled powder mixture.