Magnesium alloy and magnesium alloy die casting

Abstract

A magnesium alloy and a die casting produced from the alloy include an AZ91-based magnesium alloy including 6.0 to 11.0 percent by weight of aluminum, 0.1 to 2.5 percent by weight of zinc, 0.1 to 0.5 percent by weight of manganese, and strontium and at least one of calcium and antimony added in an amount sufficient to act as a grain refining agent.

1 . An AZ91-based magnesium alloy, comprising: 6.0 to 11.0 percent by weight of aluminum, 0.1 to 2.5 percent by weight of zinc, 0.1 to 0.5 percent by weight of manganese, and strontium and at least one of calcium and antimony added in an amount sufficient to act as a grain refining agent.  
     
     
         2 . The alloy of  claim 1 , wherein the grain refining agent comprises Sr and Ca.  
     
     
         3 . The alloy of  claim 2 , wherein the alloy comprises 1 to 3.5 percent by weight of Ca and 0.1 to 1.5 percent by weight of Sr.  
     
     
         4 . The alloy of  claim 1 , wherein the grain refining agent comprises Sr and Sb.  
     
     
         5 . The alloy of  claim 1 , wherein the grain refining agent comprises Sr, Ca and Sb.  
     
     
         6 . The alloy of  claim 5 , wherein the alloy comprises 0.05 to 3.5 percent by weight of Ca, 0.1 to 1.5 percent by weight of Sb and 0.1 to 2.5 percent by weight of Sr.  
     
     
         7 . The alloy of  claim 6 , wherein the alloy comprises 0.5 to 3.5 percent by weight of Ca, 0.5 to 1.5 percent by weight of Sb and 0.1 to 2.5 percent by weight of Sr.  
     
     
         8 . The alloy of  claim 6 , further comprising at least one element which enters gaps in a beta phase of the alloy and which divides the beta phase.  
     
     
         9 . The alloy of  claim 1 , further comprising at least one element which enters gaps in a beta phase of the alloy and which divides the beta phase.  
     
     
         10 . The alloy of  claim 9 , wherein the at least one element comprises at least one of silicon (Si): 0.1 to 1.5 percent by weight, rare earth misch metal (RE): 0.1 to 1.2 percent by weight, zirconium (Zr): 0.2 to 0.8 percent by weight, scandium (Sc): 0.2 to 3.0 percent by weight, yttrium (Y): 0.2 to 3.0 percent by weight, tin (Sn): 0.2 to 3.0 percent by weight, and barium (Ba): 0.2 to 3.0 percent by weight.  
     
     
         11 . The alloy of  claim 1 , wherein the alloy comprises at least 70 percent by weight of magnesium.  
     
     
         12 . The alloy of  claim 1 , comprising 7 to 10 percent by weight of aluminum, 0.3 to 2.1 percent by weight of zinc, 0.18 to 0.36 percent by weight of manganese, 0.1 to 1.5 by weight of Sr, and at least one of 0.5 to 2.1 percent by weight of Ca or a combination of Ca and Sb.  
     
     
         13 . A magnesium die casting comprising the alloy of  claim 1 .  
     
     
         14 . The casting of  claim 13 , wherein the casting comprises an average grain size of 20 microns or less.  
     
     
         15 . The casting of  claim 14 , wherein the casting comprises: 
 an average grain size of 13 to 19 microns;    a room temperature tensile strength of greater than 230 MPa;    a high temperature elongation of at least 29% at 175° C.;    a high temperature flow stress of at least 130 MPa at a strain rate of 10 −5  s −1 ; and    a high temperature flow stress of at least 210 MPa at a strain rate of 10 −5  s −1 , where the high temperature flow stress is measured at 175 ° C.    
     
     
         16 . The casting of  claim 13 , wherein the casting comprises an automotive part.  
     
     
         17 . An AZ91-based magnesium alloy containing a grain refining agent.  
     
     
         18 . The alloy of  claim 17 , wherein the grain refining agent comprises at least one grain refining element.  
     
     
         19 . The alloy of  claim 18 , wherein the grain refining agent comprises Sr and at least one of Sb and Ca.  
     
     
         20 . A method of making a die casting, comprising: 
 providing a melted magnesium alloy into an injection chamber of a die casting machine, wherein the alloy comprises an AZ91-based magnesium alloy which comprises 6.0 to 11.0 percent by weight of aluminum, 0.1 to 2.5 percent by weight of zinc, 0.1 to 0.5 percent by weight of manganese, and strontium and at least one of calcium and antimony added in an amount sufficient to act as a grain refining agent; and    injecting the alloy into a mold cavity to form the magnesium die casting.    
     
     
         21 . The method of  claim 20 , wherein the casting comprises an automotive part having a grain size of 20 microns or less.