Grain refinement of A356 alloy by Al-Ti-B-C master alloy and its effect on mechanical properties

A new Al-3Ti-1B-0.2C master alloy with uniform microstructure was prepared using a melt reaction method in this study. In the master alloy, TiB2 particles exhibit hierarchical dendritic morphology, while TiC particles doped with a trace amount of B show a polyhedral morphology. The grain refining performance of the master alloy on A356 alloy has also been investigated. It is found that the addition of 0.2 wt.% Al-3Ti-1B-0.2C master alloy can induce very effective grain refinement of the A356 alloy. The average grain size of alpha-Al is reduced to 167 +/- 8 mu m from about 1570 mu m and the grain refining efficiency does not fade obviously within 60 min. Therefore, the mechanical properties of the A356 alloy have been improved obviously by the addition of the Al-3Ti-1B-0.2C master alloy, including the ultimate tensile strength, yield strength and elongation. (C) 2013 Elsevier Ltd. All rights reserved.