Effect of Temperature Gradient on Primary Dendrite Spacing During Directional Solidification of Al-4.5%Cu Alloy

The drop-down 5kg crucible directional solidification equipment was used and the directional solidification experiment of Al-4.5%Cu alloy was carried out.The primary dendrite spacing of Al-4.5%Cu alloy under the conditions of different temperature gradient was studied.The results show that with the increasing of the temperature gradient,the primary dendrite spacing becomes smaller,meticulous and upright in other solidification parameters remaining unchanged.The basic shape is parallel to the distribution,meanwhile,the computed value of the primary dendrite arm spacing is closed to value with the Hunt calculated.The test measures the value of primary dendrite arm spacing in a regressive curve:y=2843478.3x2-70217.4x+543.8.With a higher temperature gradient to simulate the experimental values,the availability of λ1=26.7G-0.5-135.9 is got.The primary dendrite arm spacing λ1almost is linear with G-0.5.This is consistent with Hunt analyzed result.