アルミニウム合金及び亜鉛合金の半凝固状態における固相間隙流出と透過係数 Semi-solid Metal Flow Through Solid Network and Evaluation of Permeability for Aluminum and Zinc Alloys
In order to clarify the flow of semi-solid metal through the solid network, pressure infiltration experiments were carried out controlling the solid morphologies (globular and dendritic structures), fraction of solid, and applied pressure. Semi-solid AC4CH and ZDC2 alloys were compressed by argon gas at a pressure of 0.50MPa to force liquid components into permeating the ceramic foam filter. The results indicated that filtrated metal weight increased with pressurizing time, simultaneously yielding the consolidated grains of globular structure in the cake layer on the filter. At low fractions of solid, permeability depended strongly upon the solid morphology, namely a dendritic structure produces lower permeability due to the large flow resistance. For semi-solid AC4CH alloys with dendritic structure, cake filtration was observed for most fractions of solid. On the other hand, for semi-solid AC4CH alloy with globular structure, depth filtration was observed for low fractions of solid, <i>f</i><sub>s</sub>＜0.35. Cake filtration was prevailing for high fractions of solid, <i>f</i><sub>s</sub>＞0.35. The flow with the cake filtration mechanism is related to liquid flow through the solid network in semi-solid metals. For semi-solid ZDC2 alloy, dentritic structure is rearranged to globular structure during pressurization due to solid phase movement such as breaking off and rotation of the dendrite arms, and grain growth.
- 鋳造工学 = Journal of Japan Foundry Engineering Society
鋳造工学 = Journal of Japan Foundry Engineering Society 79(3), 139-145, 2007-03-25
Japan Foundry Engineering Society