Investigation of Grain Refinement Method for AZ91 Alloy Using Carbide Inoculation

Grain refinement is an effective method to increase both the strength and toughness of structural materials. Among the various grain refinement methods, carbon inoculation is an effective method for Mg alloys containing Al. SiC is well-known as a carbon inoculation agent; however, conventional methods for using SiC are suitable only for lab-scale experiments. This study investigates the inoculation methods with regard to the use of SiC effectively and economically for grain refinement of Mg alloys, especially for application in large-scale casting processes. Al-SiC refiner was fabricated by extrusion; it demonstrated a uniform structure with well distributed SiC particles on the Al metal matrix. After adding 0.7 wt% extruded SiC refiner, the average grain size of AZ91 alloy decreased from 550 to 90 lm. It demonstrated an effective refining ability in large-scale casting facilities.