Effect of processing parameters on microstructures of melt-spun Al-In immiscible alloys

The melt spinning rapid solidification technique was employed to fabricate homogeneous Al-In immiscible alloys, and their final microstructures and morphologies were investigated. There existed a transition of the columnar Al grain-equiaxed grain for the thicker ribbon, but only columnar Al grain for the thinner ribbon throughout the thickness. In the columnar grain field, most of the fine In particles were distributed within the cells, but a minority of bigger In particles or short rods were perpendicularly distributed at the grain boundaries. In the equiaxed grain field, fine In particles were located in the Al grains and coarser particles were situated at the boundaries. The average particle size increased with the increase of distance from the chilled surface throughout the ribbon. At the same wheel speed (the same cooling rate), the average particle size increases with the raise of In content. At the same composition condition, the average particle size decreased with the increase of wheel speed and/or the decrease of ejection temperature.