Carbides in AZ91 and their role in the grain refinement of magnesium

Investigation on the Duration of Action of Mg3N2 as a Grain Refiner for AZ80 Alloy

“…However, the grain refinement approach with zirconium [4], which is commonly used for non-Al-containing Mg alloys, does not work for this AZ Metals 2024, 14, 485 2 of 11 alloy family due to the formation of an AlZr intermetallic phase, which is ineffective for the grain refinement of Mg alloys [1]. Other grain refinement methodologies (i.e., rapid cooling, melt superheating, carbon inoculation [5][6][7], the addition of Al-Ti-C [8], B [9], Al-V-B master alloy [10], CaO [11], MgO [12,13], SiC [14], VN [15], Mg 3 N 2 [16][17][18], AlN [19], TiB 2 [20], Ca [21], the application of ultrasonic treatment [22]) have therefore been widely investigated, with a focus on the effect of particles on the grain restriction factor [23][24][25][26] and dendritic grain growth [27] as well as phase growth [28,29]. However, rapid cooling may not be a viable option for particular castings, while superheating uses extra energy and increases the oxidation of the melt.…”