Different elements-induced destabilisation of TiC and its application on the grain refinement of Mg–Al alloys

The destabilisation of TiC and its application on the grain refinement of Mg–Al alloys is studied by the experiment and CASTEP calculation. Al4C3-containing refiners for Mg–Al based alloys are easily prepared in the liquid Al–Ti–C–Si alloy, but the TiAlxSiy formed simultaneously will poison the refining efficiency of Al4C3. In contrast to Si, B element can improve the stabilization of TiC in the Al melt; however, the addition of B is essential in Al4C3-containing refiners prepared by the destabilisation of TiC in order to transfer the Ti into TiB2 particles. In this case, the poisoning effect of Ti can be avoided and the formed Al4C3 can be fully worked as the substrates for α-Mg.