Al-Si-Cu系合金の溶湯補給性と成分偏析

抄録

  Feedability of hypoeutectic Al-Si-Cu alloys greatly varies with Si and Cu contents. Consequently, the occurrence of the shrinkage porosity is different depending on the composition of the alloys, even if they are the same standard alloys. The feedability of this alloy system can be improved with an increase in Cu content and a decrease in Si content. An Al-6%Si-4%Cu alloy has the best feedability because the alloy can compensate for solidification shrinkage until its solid fraction becomes large during the eutectic solidification.
  With an increase in Cu content, however, the specific gravity near the riser of castings is lowered because of negative segregation.