Amorphization of rapidly solidified Al-Cr alloy with quasicrystal by mechanically grinding and preparing bulk material by pulsed current sintering

Abstract

An Al-Cr amorphous powder prepared by mechanically grinding a rapidly solidified ribbon was consolidated by pulsed current sintering at lower temperature than the crystallization temperature. The rapidly solidified Al_100-xCr_x(x=5-15) ribbons were prepared by single roll method. The quasicrystalline phase existed in the 7-13at%Cr ribbons. By mechanically grinding, the amorphous phase was formed in the powder of 10-15at%Cr. The analysis by XRD and DSC revealed that the mechanically ground Al₈₇Cr₁₃ and Al₈₅Cr₁₃ powders were a single amorphous phase. Al₉₀Cr₁₀ powder consisted of the Al phase and the amorphous phase. A disk specimen of 10mm in diameter was prepared by sintering at 500MPa pressure at 573K with a hard metal die. The consolidated Al₉₀Cr₁₀ had the porosity of 3.3%, while Al₈₇Cr₁₃ had the porosity of 20.7%. The marked difference between them is resulted from the mass flow of the Al in the Al₉₀Cr₁₀ sample to the triple points among the particles.