杉山 明

固相反応であるメカニカルアロイング法を用いて、FeAlの合成を試みた。Al-richな状態でミリング合成した粉末に不足分のFeを添加して成形することでFeAl金属化合物を成形できた。

  The flow behavior of solid-liquid two phase flow during mold filling effects greatly on the properties of castings such as semi-solid metal products and particle-reinforced metal matrix composites. In this study, the flow behavior of solid-liquid mixture flowing into a rectangular cavity with a core was investigated using a water-polystyrene particle mixture. The shape of the free surface of the mixture in the cavity with a core was more stable than without. Even a small core of 2mm×2mm was effective. The main reason for the phenomena is the change in the flow path of the mixture due to the core. Although gas was entrapped near the core, the amount of the gas was less for the core with the same width as the gate than the cavity without the core. The low-concentration region of solid particles appeared at the V-shaped flow boundary, which existed upward from the bottom of the core. The concentration of particles decreased at the center of the rotation of flow, which existed under, at the side of, and above the core.

The solid-liquid two phase flow influences on the properties of materials such as the semi-solid metals or the particulate-reinforced metal matrix composites. Therefore the flow phenomena of water-polystyrene mixture with high fraction solid in a suddenly enlarged cavity were examined. The mixture in an airtight vessel was ejected vertically into the cavity by increasing the internal pressure of the vessel. The shape of free surface of the mixture became more stable with increasing fraction solid. The main reason of suppressing the disturbance of the free surface is not the increase of the mean relative viscosity but the increase of fraction solid of the region near the free surface. The concentration of particles decreased at the center of rotary motion in the early stages of filling and at the boundary between the rising particles and the piled-up particles, which existed above filling ingate. It was the inertial force of particles that held the low-concentration region at the center of rotation. The low-concentration region above the ingate is caused by the collision of particles.