Non-flammable magnesium alloy with excellent mechanical properties, and preparation method thereof

Abstract

A magnesium alloy that has excellent ignition resistance and is excellent in both strength and ductility. The magnesium alloy includes, by weight, 1.0% or greater but less than 7.0% of Al, 0.05% to 2.0% of Ca, 0.05% to 2.0% of Y, greater than 0% but not greater than 6.0% of Zn, and the balance of Mg, and the other unavoidable impurities. The total content of the Ca and the Y is equal to or greater than 0.1% but less than 2.5% of the total weight of the magnesium alloy. The Mg alloy forms a dense composite oxide layer that acts as a protective film. Thus the Mg alloy has very excellent oxidation resistance and ignition resistance, can be melted, cast and machined in the air or a common inert atmosphere (Ar or N 2 ), and can reduce the spontaneous ignition of chips that are accumulated during the process of machining.

1 . A magnesium alloy manufactured by melt casting, the magnesium alloy comprising, by weight, 1.0% or greater but less than 7.0% of Al, 0.05% to 2.0% of Ca, 0.05% to 2.0% of Y, greater than 0% but not greater than 6.0% of Zn, a balance of Mg, and other unavoidable impurities,
 wherein a total content of the Ca and the Y is equal to or greater than 0.1% but less than 2.5% of a total weight of the magnesium alloy.   
     
     
         2 . The magnesium alloy of  claim 1 , wherein a content of the Ca ranges, by weight, from 0.2% to 1.5%. 
     
     
         3 . The magnesium alloy of  claim 1 , wherein a content of the Y ranges, by weight, from 0.1% to 1.5%. 
     
     
         4 . The magnesium alloy of  claim 1 , wherein contents of the Ca and the Y range from 0.3% to 2.0% of a total weight of the magnesium alloy. 
     
     
         5 . The magnesium alloy of  claim 1 , further comprising, by weight, greater than 0% but not greater than 1.0% of Mn. 
     
     
         6 . The magnesium alloy of  claim 1 , further comprising, by weight, 0.1% to 1.0% of Zr. 
     
     
         7 . A method of manufacturing a magnesium alloy, comprising:
 forming a magnesium alloy molten metal, which contains Mg, Al and Zn;   adding raw materials of Ca and Y into the magnesium alloy molten metal;   producing a magnesium alloy cast material from the magnesium alloy molten metal, in which the raw materials of Ca and Y are added, using a fusion casting method,   wherein a magnesium alloy, which is produced by the above process, comprises, by weight, 1.0% or greater but less than 7.0% of Al, 0.05% to 2.0% of Ca, 0.05% to 2.0% of Y, greater than 0% but not greater than 6.0% of Zn, a balance of Mg, and other unavoidable impurities.   
     
     
         8 . The method of  claim 7 , wherein adding the raw materials of Ca and Y into the magnesium alloy molten metal comprises adding the raw materials of Ca and Y at a temperature higher than 800° C. 
     
     
         9 . A method of manufacturing a magnesium alloy, comprising:
 forming a magnesium alloy molten metal, which contains Mg, Al and Zn;   forming a master alloy ingot, which contains Mg, Al, Zn, Ca and Y, and is soluble at 750° C. or lower;   inputting the master alloy ingot, which is soluble at 750° C. or lower, into the magnesium alloy molten metal; and   producing a magnesium alloy cast material from the molten metal, which contains the master alloy ingot, using a fusion casting method,   wherein a magnesium alloy produced as described above comprises, by weight, 1.0% or greater but less than 7.0% of Al, 0.05% to 2.0% of Ca, 0.05% to 2.0% of Y, greater than 0% but not greater than 6.0% of Zn, a balance of Mg, and other unavoidable impurities.   
     
     
         10 . The method of  claim 9 , wherein the master alloy ingot, which contains Mg, Al, Zn, Ca and Y, is soluble at 750° C. or lower, and is input into the magnesium alloy molten metal at a temperature lower than 750° C. 
     
     
         11 . A method of manufacturing a magnesium alloy, comprising:
 forming a magnesium alloy molten metal, which contains Mg, Al and Zn;   adding a Ca compound and a Y compound into the magnesium alloy molten metal; and   producing a magnesium alloy cast material from the magnesium alloy molten metal, in which the Ca compound and the Y compound are added, using a fusion casting method,   wherein a magnesium alloy produced by the above process comprises, by weight, 1.0% or greater but less than 7.0% of Al, 0.05% to 2.0% of Ca, 0.05% to 2.0% of Y, greater than 0% but not greater than 6.0% of Zn, a balance of Mg, and other unavoidable impurities.   
     
     
         12 . The method of  claim 7 , wherein inputting the raw materials of Ca and Y, the master alloy ingot, which contains Mg, Al, Zn, Ca and Y, or the Ca compound and the Y compound into the magnesium alloy molten metal further comprises periodically stirring the magnesium alloy molten metal. 
     
     
         13 . The method of  claim 7 , wherein the casting method comprises one selected from the group consisting of mold casting, sand casting, gravity casting, squeeze casting, continuous casting, strip casting, die casting, precision casting, lost foam casting, spray casting, and semi-solid casting. 
     
     
         14 . The method of  claim 7 , further comprising carrying out hot working on the magnesium alloy cast material produced by the casting method. 
     
     
         15 . The method of  claim 9 , wherein inputting the raw materials of Ca and Y, the master alloy ingot, which contains Mg, Al, Zn, Ca and Y, or the Ca compound and the Y compound into the magnesium alloy molten metal further comprises periodically stirring the magnesium alloy molten metal. 
     
     
         16 . The method of  claim 9 , wherein the casting method comprises one selected from the group consisting of mold casting, sand casting, gravity casting, squeeze casting, continuous casting, strip casting, die casting, precision casting, lost foam casting, spray casting, and semi-solid casting. 
     
     
         17 . The method of  claim 9 , further comprising carrying out hot working on the magnesium alloy cast material produced by the casting method. 
     
     
         18 . The method of  claim 11 , wherein inputting the raw materials of Ca and Y, the master alloy ingot, which contains Mg, Al, Zn, Ca and Y, or the Ca compound and the Y compound into the magnesium alloy molten metal further comprises periodically stirring the magnesium alloy molten metal. 
     
     
         19 . The method of  claim 11 , wherein the casting method comprises one selected from the group consisting of mold casting, sand casting, gravity casting, squeeze casting, continuous casting, strip casting, die casting, precision casting, lost foam casting, spray casting, and semi-solid casting. 
     
     
         20 . The method of  claim 11 , further comprising carrying out hot working on the magnesium alloy cast material produced by the casting method.