一方向凝固したAl-Cu合金の凝固組織に関する研究

概要

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Primary and secondary dendrite arm spacing increases with decreasing average cooling velocity. But primary arm spacing increases with Cu content, while secondary arm spacing does not change appreciably with Cu content over the composition range investigated. The relationships between these were obtained as follows; λ1=0.87√Co/Va, λ2=177Va−1/3where, λ1 is the primary arm spacing (mm), Co is the Cu content (%), Va the average cooling velocity (°C/min) and λ2 the secondary arm spacing (μ). As the solidification rate increases, the size and mean free path of the θ phase show an appreciable decrease. And the mean free path between θ-particles is similar to the order of the secondary dendrite arm spacing. With decreasing distance from the chill face (that is, increasing solidification rate), the amount of θ phase decreases over the range of solidification conditions investigated in this paper. As distance from chill becomes smaller, lattice constant decreases, and the Cu-content in α-matrix increased. From these results, the behavior of second phase in unidirectionally solidified Al-Cu alloys could be confirmed quantitatively.
Japan Foundry Engineering Societyの論文