Magnesium-aluminum based alloy

Abstract

The present invention relates magnesium-aluminum based alloys having a small grain size and to a method of their production. The alloys are particularly useful in casting applications. The alloys comprise a grain refiner, the grain refiner having the chemical formula: Mg 100-x-y-z Al x C y R z wherein R is an element selected from the group consisting of silicon, calcium, strontium or a rare earth element, x is from 10 to 60 At. %, y is from 5 to 50 At. %, and z is from 0 to 20 At. %, provided that x+y+z is less than 100 At. %.

1 . A magnesium-aluminum alloy comprising a grain refiner, the grain refiner having the chemical formula:
   Mg 100-x-y-z Al x C y R z      wherein R is an element selected from the group consisting of silicon, calcium, strontium or a rare earth element, x is from 10 to 60 At. %, y is from 5 to 50 At. %, and z is from 0 to 20 At. %, provided that x+y+z is less than 100 At. %.   
     
     
         2 . The magnesium-aluminum alloy according to  claim 1 , which comprises the grain refiner in an added amount of 0.1 to 2% by weight of the initial weight of the alloy. 
     
     
         3 . The magnesium-aluminum alloy according to  claim 1 , wherein the rare earth element is selected from the group consisting of lanthanum, cerium, neodymium, samarium, europium and rare earth mischmetal. 
     
     
         4 . The magnesium-aluminum alloy according to  claim 1 , wherein the magnesium-aluminum alloy is selected from the group consisting of magnesium-aluminum-zinc alloys and magnesium-aluminum-manganese alloys. 
     
     
         5 . The magnesium-aluminum alloy according to  claim 4 , wherein the alloy is selected from the group consisting of AM50, AM60, AM201, AZ10, AZ31, AZ63, AZ80, AZ91, AE44, AE42, AJ53, AS41 and AS42. 
     
     
         6 . A method for producing a magnesium-aluminum alloy having fine grain, which comprises melting an alloy comprising magnesium and aluminum under a protective gas atmosphere, adding to the molten magnesium-aluminum alloy a grain refiner according to  claim 1 , and allowing the alloy to solidify. 
     
     
         7 . The method of  claim 6 , wherein the molten magnesium-aluminum alloy comprising the grain refiner is cast prior to allowing the alloy to solidify. 
     
     
         8 . The method of  claim 6 , wherein the protective gas comprises argon. 
     
     
         9 . The method of  claim 6 , wherein the protective gas further comprises SF6. 
     
     
         10 . The method according to  claim 6 , wherein the grain refiner is used in the form of a milled powder having a particle size of less than 50 nm. 
     
     
         11 . The method according to  claim 6 , wherein the molten magnesium-aluminum alloy is stirred between 10 minutes and 60 minutes after adding the grain refiner. 
     
     
         12 . The method of  claim 6 , wherein the protective gas comprises argon. 
     
     
         13 . The method according to  claim 7 , wherein the grain refiner is used in the form of a milled powder having a particle size of less than 50 nm. 
     
     
         14 . The method according to  claim 8 , wherein the grain refiner is used in the form of a milled powder having a particle size of less than 50 nm. 
     
     
         15 . The method according to  claim 9 , wherein the grain refiner is used in the form of a milled powder having a particle size of less than 50 nm. 
     
     
         16 . The magnesium-aluminum alloy according to  claim 2 , wherein the rare earth element is selected from the group consisting of lanthanum, cerium, neodymium, samarium, europium and rare earth mischmetal. 
     
     
         17 . The magnesium-aluminum alloy according to  claim 2 , wherein the magnesium-aluminum alloy is selected from the group consisting of magnesium-aluminum-zinc alloys and magnesium-aluminum-manganese alloys. 
     
     
         18 . The magnesium-aluminum alloy according to  claim 3 , wherein the magnesium-aluminum alloy is selected from the group consisting of magnesium-aluminum-zinc alloys and magnesium-aluminum-manganese alloys. 
     
     
         19 . The method of  claim 6 , wherein the grain refiner is added in an amount of 0.1 to 2% by weight of the initial weight of the alloy. 
     
     
         20 . The method of  claim 6 , wherein the rare earth element is selected from the group consisting of lanthanum, cerium, neodymium, samarium, europium and rare earth mischmetal.