Pulsed Current Sintering of Rapidly Solidified Al-Cr-Si Powder with Quasicrystal

Abstract

The thermal characteristic and the structure of rapidly solidified Al-Cr-Si ribbons by single roll melt spinning were examined and ability of sintering by pulsed current sintering was investigated. A single phase of quasicrystal is produced in Al₇₄Cr₂₀Si₆, and a mixed phase of Al and quasicrystal was produced in Al₇₇Cr₁₃Si₁₀. The mixed phase of Al and quasicrystal was produced in Al₉₀Cr_xSi_(10-x) (x=3,6,8,10), also. The quasicrystal in Al₉₀Cr_xSi_(10-x) x=3, 6, 8) ternary system was different thermal stability from the quasicrystal in Al₉₀Cr₁₀ binary system because of with a different quasicrystalline structure. The transform temperature of the quasicrystal to a stable phase in Al-Cr-Si ternary system was 100 degree higher than Al-Cr binary alloy. The porosity of a sintered material decreased with increasing Al phase in the rapidly solidified powder from the result of sintered Al₇₄Cr₂₀Si₆, Al₇₇Cr₁₃Si₁₀ and Al₉₀Cr₆Si₄, and Al₉₀Cr₆Si₄ was the highest density. The effect of sintering temperature and applied pressure on sintering density was investigated in Al₉₀Cr₆Si₄. The sintering density at 513K in 500MPa was above 99%. Then, the sintering density at 613K in 250MPa was 99% or more, and the applied pressure could be decreased in half.