Method for grain refinement of magnesium alloy castings

Abstract

A method for grain refinement of magnesium alloy castings includes adding graphite (C) powder and manganese dioxide (MnO 2 ) to a melt of magnesium alloy containing aluminum (Al) and manganese (Mn) to finely divide crystal grains of a cast structure.

What is claimed is:  
     
         1 . A method for grain refinement of magnesium alloy casting, comprising adding graphite (C) powder and manganese dioxide (MnO 2 ) to a melt of magnesium alloy containing aluminum (Al) and manganese (Mn) to refine crystal grains of a cast structure.  
     
     
         2 . The method according to  claim 1 , wherein said graphite (C) powder and said manganese dioxide (MnO 2 ) are accommodated in a metallic capsule.  
     
     
         3 . The method according to  claim 2 , wherein said metallic capsule is formed of pure aluminum or aluminum alloy.  
     
     
         4 . The method according to  claim 2 , wherein said metallic capsule is formed of pure magnesium or magnesium alloy.  
     
     
         5 . The method according to  claim 1 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.10 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         6 . The method according to  claim 2 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.10 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         7 . The method according to  claim 3 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.10 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         8 . The method according to  claim 4 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.10 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         9 . The method according to  claim 1 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.20 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         10 . The method according to  claim 2 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.20 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         11 . The method according to  claim 3 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.20 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.  
     
     
         12 . The method according to  claim 4 , wherein said manganese dioxide (MnO 2 ) has an amount in the range of 0.20 mass % to 0.22 mass % based on a mass of the melt of said magnesium alloy.