摘要
The effects of pulling velocity on the solidification behavior and microstructural parameters of A1Sil0Mg alloys prepared in a Bridgman-type directional solidification furnace were investigated. The microstructure, particularly the secondary dendritic arm spacing （SDAS）, and the Brinell hardness （BH） of the solidified A1Sil0Mg alloys were characterized for samples with cylindrical shapes and differ- ent conicities （θ = 0°, 5°, and 10°）. Microstructural studies revealed an increased density of ct-A1 phase dendrites and a decreased interden- dritic distance with increasing pulling velocity. The dendrites were found to be preferentially oriented along the pulling direction for low pulling velocities. For larger pulling velocities, the dendrites grew first in the cooling direction but then broke as others nucleated and coars- ened. The HB values of the solidified samples increased as the pulling velocity increased. In regard to sample conicity, smaller dendrites were observed for an apex angle of θ = 5°, resulting in the largest HB value. This result was interpreted in terms of the favorable orientation of the dendrite along the pulling direction.
The effects of pulling velocity on the solidification behavior and microstructural parameters of A1Sil0Mg alloys prepared in a Bridgman-type directional solidification furnace were investigated. The microstructure, particularly the secondary dendritic arm spacing （SDAS）, and the Brinell hardness （BH） of the solidified A1Sil0Mg alloys were characterized for samples with cylindrical shapes and differ- ent conicities （θ = 0°, 5°, and 10°）. Microstructural studies revealed an increased density of ct-A1 phase dendrites and a decreased interden- dritic distance with increasing pulling velocity. The dendrites were found to be preferentially oriented along the pulling direction for low pulling velocities. For larger pulling velocities, the dendrites grew first in the cooling direction but then broke as others nucleated and coars- ened. The HB values of the solidified samples increased as the pulling velocity increased. In regard to sample conicity, smaller dendrites were observed for an apex angle of θ = 5°, resulting in the largest HB value. This result was interpreted in terms of the favorable orientation of the dendrite along the pulling direction.
基金
financially supported by the doctoral scholarship grant of the Algerian-MHESR
