Calculation of Jackson’s factor of Mg2Si in Mg melt using coordination polyhedron

• Coordination polyhedron is used as a growth unit to calculate Jackson’s factors.
• Jackson’s factors of three low Miller-index crystal planes of Mg2Si are calculated.
• Crystal habit of primary Mg2Si in Mg melt is predicted.

The Jackson’s factors of three low Miller-index crystal planes of Mg2Si were calculated with a rough interface model by using a growth unit of coordination polyhedron instead of atom. The Jackson’s factors of the {1 0 0}, {1 1 0} and {1 1 1} planes were obtained to be 2.53, 1.27 and 3.80, respectively. The physical meaning of using coordination polyhedron to calculate the Jackson’s factor was interpreted reasonably. The thermodynamic possibility of growing units onto a solid/liquid interface was linked to the microscopic appearance of crystal planes and to the macroscopic shape of Mg2Si crystals formed.