Al-Si系合金鋳物の逆偏析層厚さに及ぼすSi, P, 金型温度の影響

抄録

  In order to clarify the effects of Si, P and mold temperature on the reverse segregation layer thickness in Al-Si system alloy castings, investigations were carried out by microstructure observation. The results are as follows. The reverse segregation layer was observed in Al-7% Si alloy but not Al-12.6% Si alloy. The reverse segregation layer thickness of Al-7%-0.002%P alloy was thicker than that of Al-7%-0%P alloy. The solidified shell thickness was thin for high mold temperatures. The reverse segregation layer thickness was determined from the solidified shell forming time. The eutectic silicon in the second layer (solidified shell) of Al-7%Si-0%P alloy had a round shape similar to that seen when solution treatment is carried out during the formation of air gaps. The formation mechanism of four layers on the surface in Al-7%Si-0%P alloy was also reviewed.