Microstructure of aluminum-lithium alloys obtained with directional solidification

The aluminum - lithium alloys are of important use in the auto and aerospace industry. It is generally accepted that good solidification structures are required for performance. In the present report the solidification structure of these alloys are studied experimentally. Alloys containing Al, Li and Cu were directionally solidified under different conditions of temperature gradients and velocities; the alloys also contained grain refiners. The alloys with added refiners were completely equiaxed. The dendritic structures were analyzed with scanning electron microscopy and image analyzer. The secondary dendritic spacings were measured and the results were compared and correlated with the models available in the literature.