Effect of potent TiB2 addition levels and impurities on the grain refinement of Al

Abstract In the present work, the effect of potent TiB 2 particle addition levels and impurities on the grain refinement of two Al compositions was investigated. Results showed that no effective grain refinement was achieved in high purity Al (HP-Al) up to particle density levels as high as 2.5 × 10 14 /m 3 . In commercial purity Al (CP-Al) fine grain refined structures were observed with merely a particle density of 0.35 × 10 13 /m 3 . As more particles were added into the CP-Al melt, the number of grains formed showed an overall increase while the calculated particle efficiency showed a general decrease, consistent with the prediction of interdependence theory. Such results show that the impurities in CP-Al play a significant role in refining the grain structures.