EFFECTS OF AMBIENT-TEMPERATURE AND ACCELERATION ON VARIOUS MECHANICAL ALLOYING PRODUCTS - MG-AL-ZN QUASI-CRYSTALS, NI-ZR AMORPHOUS-ALLOYS AND AMORPHOUS SE

In the present work, we employed a high-energy mill which is capable of milling with intensities up to 150G (where G is the gravity of the earth) in ambient temperatures up to 300-degrees-C. Phase transformation diagrams were constructed as functions of milling intensity and ambient temperature for three representative systems: Mg48Al15Zn37, Ni50Zr50 and pure Se. The ambient temperature measured on the outer wall of the vial was found to coincide well with the true ''annealing'' temperature which the powdered sample experiences during milling. It is shown that both the milling intensity and ambient temperature affect substantially the formation rate of a quasicrystal in the Mg-Al-Zn system and that of an amorphous phase in both Ni-Zr and Se. By choosing appropriate conditions, we found the shortest milling times to complete the formation of Mg-Al-Zn quasicrystals, amorphous Ni-Zr alloy and Se to be 30 min, 3 h and 20 min respectively.