Numerical and Experimental Investigations into the Effects of Complex Geometry on the Mechanical Performance of Aluminum 6063 Alloy.

Abstract

This study investigates the relationship between variations in the geometric configurations of an aluminum alloy’s complex structure and the evolution of its tensile property towards improving its mechanical performance. A prototype aluminum 6063 structure with geometric features of tapered cylinder, convergent cones, cylinder, and stepped cuboids was designed. The heat transfer and solidification analysis were simulated on the structure in the ANSYS software environment to obtain the cooling rates at each of the change of sections. A heat transfer model was used to calibrate the geometric constraints. The experimental validation was performed by sand-casting. The geometric constraints were modeled with variable-sized chills of representative heat transfer coefficients and the temperature-time-history was obtained during casting. Mechanical tests were conducted at the change of sections and the tensile behavior was obtained. The results showed that variability of the heat transfer coefficients corresponds to associated variability in mechanical performance which is in agreement with the simulations. The effect of variations in the cooling rates across the complex geometry suggests that tensile behavior can be closely controlled. Microstructural investigations also confirmed that by controlling temperature gradients, the morphology of the alloy can be tuned for better mechanical performance.