Fabrication of Lotus--type Porous Al-Si Alloys using Continuous Casting Technique

摘要

Lotus-type porous Al-Si (4, 8, 12, 14 and 18 wt. percent) alloys were fabricated using continuous casting technique under the hydrogen gas pressure of 0.1 MPa at transference velocity of 2.0 mm min~(-1), and the effects of the silicon content on the pore morphology and porosity were investigated. Both the porosity and the average pore diameter increased with increasing silicon content. The pore shape was changed from irregular in the higher dendrite fraction to nearly circular in the lower dendrite fraction. The porosity and the pore morphology were influenced by the silicon content. These results can be explained by the model that the pores which contribute to increase of porosity are generated at the eutectic fronts.