Mechanism for Grain Refinement and Mechanical Properties of AZ91 Mg Alloy by Carbon Inoculation

The effect of charcoal on the grain refinement and mechanical properties of the AZ91 is investigated in the present study. The results show addition of 0.4 wt% charcoal produced maximum grain refinement in the AZ91 Mg alloy by reducing the grain size from 100 to 14 μm. Such fine grain structure achieved through addition of charcoal suggests that the Al4C3 and Al2MgC2 particles formed in the melt have acted as efficient nucleating sites during solidification of α-Mg. Significant improvement in mechanical properties observed with charcoal addition is attributed to the grain refinement and the presence of fine carbide particles.