Role of self-inoculants in solidification process of AZ91D magnesium alloy

The role of self-inoculants with various original microstructure in solidification process of AZ91D magnesium alloy was studied by quenching. The experimental results show that the melt temperature field is changed because of introduction of self-inoculants, which makes local supercooling in the melt. And thus a feasible place is gained for nucleation. Consequently, nucleation rate of the melt is increased. The self-inoculants appeared the half-cooked residue when the parameters of melt treatment are controlled unsuitably. The dendrite fragments generated from dendrite remelting and distribute in the liduids around remelted dendrites, provid the seed crystals of alloy refining by itself. During self-inoculation process, the ‘second inoculation’ of melt is induced from cooling channel, and which provides the ideal condition of formation of tiny dendrite and small granular grains.