The effect of cooling rate on the solidification microstructure, solidification and segregation behavior of 7075 and 7050 aluminum alloy was investigated. Samples were solidified with cooling rates between 0.3 and 17°K/sec. Using the cooling curve of each sample, liquidus, eutectic and intermetallic reaction temperature were estimated. The microstructures are characterized in terms of dendrite arm spacing and eutectic volume fraction. The segregation behavior of each alloying element of these alloys in various cooling rates was discussed. And adding the $AlTi_5B_1$ based alloys, grain refinement effect of these alloying was investigated.
Further, solute distribution of Al-Cu binary alloy during solidification was calculated. For simplification, constatnt temperature gradient and cooling rate were assumed. These conditions are for the directional solidification. Dendrite tip velocity was calculated using KGT model and parabolic shape of dendrite morphology was assumed. Solute diffusion was calculated by using Finite Difference Method. Predicted data are found to be in agreement with the experimental observations.
