| Abstract |
| Grain refinement of cast magnesium alloys containing Al is successfully attained using MnCO3 as a grain refiner. However, the direct addition of MnCO3 in a magnesium melt causes the oxidation and ignition of the melt due to the gases that formed during the decomposition of MnCO3. To improve the effectiveness and safety of the MnCO3 addition process, inoculation was conducted by adding an Al master alloy with MnCO3. The Al master alloy was prepared using cylindrical pressed pellets composed of a mixture of MnCO3 powders and metal chips in the aluminum melt. The results revealed that the inoculation method using the Al master alloy is more effective and stable than previously used methods. The grain size of the as-cast AZ91 Mg alloy was significantly decreased from 420 to 70um by adding the Al master alloy of 3 wt%, which is mainly attributed to the formation of thermally stable Al4C3 particles as an effective grain refiner in the melt. |
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| Key Words |
| metals, casting, grain refinement, optical microscopy, magnesium |
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