Effect of trace boron on grain refinement of commercially pure aluminum by Al–5Ti–1B

Abstract

The effect of boron content on grain refinement of commercially pure aluminum by Al–5Ti–1B was quantitatively assessed. When the boron content is less than 0.03 wt.%, the refining performance of Al–5Ti–1B gradually is weakened as the boron content increases, which is attributed to the reaction of boron with the Al3Ti interlayer on TiB2 and the consumption of solute Ti. On the contrary, when the boron content exceeds 0.03 wt.%, the refining performance of Al–5Ti–1B gradually recovers with increasing boron content, which is related to the formation of primary AlB2 particles that provide additional nucleant substrates.