Abstract

Electro-Discharge Sintering (EDS) employs a high-voltage/high-current-density pulse of electrical energy, discharged from a capacitor bank, to instantaneously consolidate powders. In the present study, a single pulse of 0.57-1.1 kJ/0.45 g-atomized spherical Ti_52Zr_28Ni_20 powders in size range of 10~30 and 30sim50µm consisting of beta-(Ti, Zr) and icosahedral phases were applied to examine the structural evolution of icosahedral phase during EDS. Structural investigation reveals that high electrical input energy facilitates complete decomposition of icosahedral phase into C14 laves and beta-(Ti, Zr) phases. Moreover, critical input energy inducing decomposition of the icosahedral phase during EDS depends on the size of the powder. Porous Ti and W compacts have been fabricated by EDS using rectangular and spherical powders upon various input energy at a constant capacitance of 450µF in order to verify influence of powder shape on microstructure of porous compacts. Besides, generated heat (DeltaH) during EDS, which is measured by an oscilloscope, is closely correlated with powder size.

• Keywords: Powder metallurgy;Porous compact;Quasicrystals;Electro discharge sintering;