Effect of concentration-gradient on characteristic parameters of α-Al dendrites in Al-Cu alloy

The α-Al dendrites of the Al–Cu alloy can maintain directional growth under concentration-gradient. Primary and secondary dendrite arm spacings, denoted λ1 and λ2, respectively, were measured to determine the Al–Cu concentration-gradient alloys that were solidified directionally at various concentration gradients (Gc), concentration (C) and cooling rates (RT). The λ1 and λ2 were expressed as functions of solidification parameters by using a regression analysis. The results were in good agreement with previous experimental work. This study provides some regression mathematical models to predict the microstructure of concentration-gradient alloys based on process parameters of the concentration-gradient, concentration and cooling rate, and it provides a path to design the properties of concentration-gradient alloys.