EngagedScholarship@CSU Directional Solidification of Al-7 WT Si Alloy DIRECTIONAL SOLIDIFICATION OF Al-7 WT % Si ALLOY Kambow for their help and friendship. I also greatly appreciate the support from Ms DIRECTIONAL SOLIDIFICATION OF Al-7 WT % Si ALLOY

Ravi Rajamure, Ravi Rajamure, Cleveland, Siva Ramasamy, P Swapna, Ufuk Reddy, Mr Sarikaya, Sumit, Ms Laird, Montgomery, Janardhan Reddy, R Yeshodha (+13 others)
2005 unpublished
Al-7 wt % Si alloy has been directionally solidified from an aluminum single crystal seed with its [100] orientation parallel to the growth direction with a positive thermal gradient of 40 K/cm and over the range of growth speeds. Growth speed dependence of primary Dendrite Spacing and Primary Dendrite trunk Diameter has been analyzed during the step increase and step decrease in the growth speeds. Frequency distribution of Nearest Neighbor dendrites obtained from the statistical analysis shows
more » ... the hexagonal distribution of dendrites. The interdendritic convection was present in the form of transverse macrosegregation and non uniform distribution of dendrites at low growth speeds, 4 and 5 µm/s. The samples grown at higher growth speed of 22 and 72 µm/s did not show the microstructure inhomogeneity. An increase in the growth speed shows decrease in primary dendrite arm spacing which is in agreement with theoretical models. One unanticipated finding was that the primary dendrite spacing predicted by the Hunt-Lu model is small when compared with the experimental Spacing. The Current investigation showed that steady state distribution is achieved after a solidification distance of 3 mushy zone lengths after the change in speed. VI