Impurity Distribution after Solidification of Hypereutectic Al-Si Melts and Eutectic Al-Si Melt

Hypereutectic Al-Si melts and eutectic Al-Si melt were solidified to study boron and phosphorus distributions in primary silicon phase, eutectic silicon phase and eutectic aluminum phase during Al-Si solvent refining. The boron and phosphorus contents in the primary silicon phase and the eutectic silicon phase were determined by ICP-OES, and the boron and phosphorus contents in the eutectic aluminum phase were calculated by the principle of mass conservation. The primary silicon phase has lowest boron and phosphorus contents, while the eutectic aluminum phase has highest boron and phosphorus contents.

Characterization of mechanically milled and spark plasma sintered Al2124-CNT nanocomposites

In the present work, ball milling and spark plasma sintering were used to develop Al2124-CNT nanocomposites. The effect of milling time on the grain size and lattice strain of the ball milled Al2124 alloy powder and the effect of sintering time and temperature on the grain size of the matrix in spark plasma sintered Al2124 alloy and CNT-reinforced Al2124 nanocomposites were investigated. The density and hardness of the developed materials were evaluated as functions of the sintering parameters. It was found that ball milling not only reduced the particle size of the Al2124 powder but also decreased the grain size of the ?-aluminum phase to 50 nm and increased its lattice strain. A milling time of 6 hours was found to be the optimum time to reach a nanostructured ?-aluminum matrix. The grain size of the ?-aluminum phase in the sintered samples increased with increasing sintering temperature and time to reach maximum values at a sintering temperature of 500?C and a sintering time of 20 minutes. Although sintering led to grain growth, the grain size of the ?-aluminium matrix remained in the nanometer range and did not exceed 150 nm. The relative density and hardness of the sintered samples increased with increasing sintering temperature and time to reach maximum values at a sintering temperature of 500?C and a sintering time of 20 minutes.