Tadayoshi Takahashi1, Masayuki Kudoh1 and Kiyoshi Ichikawa2
1Department of Metallurgical Engineering, Faculty of Engineering, Hokkaido University, Sapporo
The solid-liquid coexisting zone was classified into the q and the p zone by the fluidity of the liquid between solids. In the q zone having the range of mass fractions of solid of 0 to 0.67, the liquid between the solids can flow, and in the p zone, which has the range of 0.67 to 1.0, the liquid is entrapped by the solids and cannot flow through the solids. The solidification ranges of the q and the p zones were evaluated by the diffusion-controlled equation introducing the term of the mean solute concentration in solid and are shown in the equilibrium phase diagram of an Al-base binary alloy. The flow length in the fluidity test of binary alloys was corresponding to the reciprocal of the solidification range of the q zone. The strength during solidification originated at a mass fraction of solid of 0.67 on the boundary between the q and the p zones, increased with increasing fraction of solid and rapidly increased at the end of solidification. The crack length in the ring test of binary alloys increased with the width of the primary crystallization in the p zone and the fraction of volume contraction in its zone.
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