Grain refinement of Mg-Li-Al cast alloys by adding typical master alloys

Commercial Al-3Ti-1C and Al-5Ti-1B master alloys were added in order to refine the grains of Mg-Li-Al alloys. The effects of their addition levels on grain refinement of Mg-Li-Al cast alloy were investigated and the mechanism of the grain refinement was discussed. The results showed that the addition of Al-3Ti-1C master alloy reduced the grain size of LA141 cast alloy from 900 μm to 400 μm, while the addition of Al-5Ti-1B master alloy reduced the grain size of LA51 cast alloy from 500 μm to 240 μm. The grain refining mechanism was the heterogeneity nucleation of TiC and TiB2, because of less than 10% mismatches of TiC/β-Li and TiB2/α-Mg.