Magnesium wrought alloy having improved extrudability and formability

Abstract

In one aspect, the invention provides a magnesium-based casting alloy having relatively high strength and castibility, as well as an improved ductility and extrudability for wrought alloy applications. The magnesium-based wrought alloy comprises aluminum (Al) of between about 2.5 to about 4.0 wt. %, manganese (Mn) of less than about 0.6 wt. %, zinc (Zn) of less than about 0.3 wt. %, other impurities of less than about 0.1 wt. %, and a balance of magnesium (Mg). The invention further provides methods of forming a wrought alloy component and automotive components formed therefrom.

1 . A metal alloy comprising: 
 aluminum (Al) from about 2.5 to about 3.5 wt. %; manganese (Mn) from about 0.2 to about 0.6 wt. %; zinc (Zn) less than about 0.3 wt. %; one or more impurities collectively less than about 0.1 wt. %; and a balance of magnesium (Mg).    
     
     
         2 . The metal alloy according to  claim 1 , wherein said aluminum is about 3 wt. %.  
     
     
         3 . The metal alloy according to  claim 1 , wherein said manganese is about 0.4 wt. %.  
     
     
         4 . The metal alloy according to  claim 1 , wherein said composition comprises said aluminum (Al) of about 3 wt. %; said manganese (Mn) of about 0.4 wt. %; and said zinc (Zn) less than about 0.22 wt. %.  
     
     
         5 . The metal alloy according to  claim 1 , wherein said one or more impurities comprise: silicon (Si) of less than about 0.01 wt. %, copper (Cu) of less than about 0.01 wt. %, nickel (Ni) of less than about 0.002 wt. %, iron (Fe) of less than about 0.002 wt. %, and one or more additional impurities of less than about 0.02wt. %.  
     
     
         6 . The metal alloy according to  claim 1 , wherein the alloy has an elongation of greater than 8% at room temperature.  
     
     
         7 . The metal alloy according to  claim 1 , wherein the alloy has an extrusion speed of greater than 305 mm per minute at 360° C.  
     
     
         8 . The metal alloy according to  claim 1 , wherein the alloy has a yield strength of greater than about 165 MPa.  
     
     
         9 . The metal alloy according to  claim 1 , wherein the alloy has an ultimate tensile strength of greater than about 230 MPa.  
     
     
         10 . The metal alloy according to  claim 1 , wherein the alloy is corrosion resistant.  
     
     
         11 . A magnesium-based wrought alloy having a composition comprising: 
 aluminum (Al) of between about 2.5 to about 4.0 wt. %; manganese (Mn) and zinc (Zn) collectively present at less than about 1.0 wt. %; impurities collectively less than about 0.1 wt. %; and a balance of magnesium (Mg).    
     
     
         12 . The magnesium-based wrought alloy according to  claim 11 , wherein the composition comprises aluminum (Al) from about 2.5 to about 3.5 wt. %; manganese (Mn) from about 0.2 to 0.6 wt. %; zinc (Zn) less than about 0.3 wt. %; one or more impurities of less than about 0.1 wt. %; and a balance of magnesium (Mg).  
     
     
         13 . The magnesium-based wrought alloy according to  claim 11 , wherein the composition comprises manganese (Mn) from about 0.26 wt. % to about 0.6 wt.%; and zinc (Zn) less than 0.22 wt. %.  
     
     
         14 . The magnesium-based wrought alloy according to  claim 11  above, wherein said one or more impurities comprise: silicon (Si) of less than about 0.01 wt. %, copper (Cu) of less than about 0.01 wt. %, nickel (Ni) of less than about 0.002 wt. %, iron (Fe) of less than about 0.002 wt. %, and one or more additional impurities of less than about 0.02 wt. %.  
     
     
         15 . The magnesium-based wrought alloy according to  claim 11 , wherein said aluminum is about 3 wt. %.  
     
     
         16 . The magnesium-based wrought alloy according to  claim 11 , wherein said manganese is about 0.4 wt. %.  
     
     
         17 . The magnesium-based wrought alloy according to  claim 11 , wherein the composition comprises said aluminum (Al) of about 3 wt. %; said manganese (Mn) from about 0.4 wt. %; said zinc (Zn) less than about 0.22 wt. %; said one or more impurities of less than about 0.1 wt. %; and a balance of said magnesium (Mg).  
     
     
         18 . The magnesium-based wrought alloy according to  claim 11 , wherein the wrought alloy has an elongation of greater than 8% at room temperature.  
     
     
         19 . The magnesium-based wrought alloy according to  claim 11 , wherein the wrought alloy has an extrusion speed of greater than 305 mm per minute at 360° C.  
     
     
         20 . The magnesium-based wrought alloy according to  claim 11 , wherein the wrought alloy has a yield strength of greater than about 165 MPa.  
     
     
         21 . The magnesium-based wrought alloy according to  claim 11 , wherein the wrought alloy has an ultimate tensile strength of greater than about 230 MPa.  
     
     
         22 . The magnesium-based wrought alloy according to  claim 11 , wherein the wrought alloy is corrosion resistant.  
     
     
         23 . A method of forming a wrought alloy element comprising: 
 forming a molten alloy material having a composition comprising aluminum (Al) of less than about 4.0 wt. %; manganese (Mn) and zinc (Zn) collectively present at less than about 1.0 wt. %; one or more impurities collectively less than about 0.1 wt. %; and a balance of magnesium (Mg), at a casting temperature;    cooling said alloy material to solidify; and    processing said solidified alloy material by deformation, thereby forming the wrought alloy element.    
     
     
         24 . The method according to  claim 23 , wherein said composition comprises aluminum (Al) from about 2.5 to about 3.5 wt. %; manganese (Mn) from about 0.2 to about 0.6 wt. %; and zinc (Zn) less than about 0.3 wt. %.  
     
     
         25 . The method according to  claim 23 , wherein said composition comprises manganese (Mn) from about 0.26 to about 0.6 wt. %; and zinc (Zn) less than about 0.22 wt. %.  
     
     
         26 . The method according to  claim 23  above, wherein said one or more impurities comprise: silicon (Si) of less than about 0.01 wt. %, copper (Cu) of less than about 0.01 wt. %, nickel (Ni) of less than about 0.002 wt. %, iron (Fe) of less than about 0.002 wt. %, and additional impurities of less than about 0.02 wt. %.  
     
     
         27 . The method according to  claim 23 , wherein said solidified alloy material comprises an ingot.  
     
     
         28 . The method according to  claim 23 , wherein said solidified alloy material comprises a billet.  
     
     
         29 . The method according to  claim 23 , wherein said casting temperature is greater than about 600° C.  
     
     
         30 . The method according to  claim 23 , wherein said processing comprises a hot-working process.  
     
     
         31 . The method according to  claim 23 , wherein said processing comprises a cold-working process.  
     
     
         32 . The method according to  claim 23 , wherein said processing is selected from the group consisting of: extruding, rolling, bending, hydroforming, stamping, superplastic forming, gas forming, electromagnetic forming, and combinations thereof.  
     
     
         33 . The magnesium-based wrought alloy according to  claim 23 , wherein said aluminum is about 3 wt. %.  
     
     
         34 . The method according to  claim 23 , wherein said manganese is about 0.4 wt. %.  
     
     
         35 . The method according to  claim 23 , wherein the composition comprises said aluminum (Al) of about 3 wt. %; said manganese (Mn) of about 0.4 wt. %; said zinc (Zn) less than about 0.22 wt. %; said one or more impurities of less than about 0.1 wt. %; and a balance of said magnesium (Mg).  
     
     
         36 . The method according to  claim 23 , wherein said processed alloy material has an elongation of greater than 8% at room temperature.  
     
     
         37 . The method according to  claim 23 , wherein said processed alloy material has an extrusion speed of greater than 305 mm per minute at 360° C.  
     
     
         38 . The method according to  claim 23 , wherein said processed alloy material has a yield strength of greater than about 165 MPa.  
     
     
         39 . The method according to  claim 23 , wherein said processed alloy material has an ultimate tensile strength of greater than about 230 MPa.  
     
     
         40 . The method according to  claim 23 , wherein said processed alloy material is corrosion resistant.  
     
     
         41 . A component for use in a vehicle comprising a magnesium-based wrought alloy comprising aluminum (Al) of less than about 4.0 wt. %; manganese (Mn) and zinc (Zn) collectively present at less than about 1.0 wt. %; one or more impurities collectively less than about 0.1 wt. %; and a balance of magnesium (Mg).  
     
     
         42 . The component according to  claim 41 , wherein said alloy comprises aluminum (Al) from about 2.5 to about 3.5 wt. %; manganese (Mn) from about 0.2 to 0.6 wt. %; and zinc (Zn) less than about 0.3 wt. %.  
     
     
         43 . The component according to  claim 41 , wherein said alloy comprises manganese (Mn) from about 0.26 to about 0.6 wt. % and zinc (Zn) less than about 0.22 wt. %.  
     
     
         44 . The component according to  claim 41 , wherein said one or more impurities comprise: silicon (Si) of less than about 0.01 wt. %, copper (Cu) of less than about 0.01 wt. %, nickel (Ni) of less than about 0.002 wt. %, iron (Fe) of less than about 0.002 wt. %, and additional impurities of less than about 0.02 wt.  
     
     
         45 . The component according to  claim 41 , wherein said alloy forms a tubular structure.  
     
     
         46 . The component according to  claim 41 , wherein said alloy forms a rolled structure.  
     
     
         47 . The component according to  claim 41 , wherein said alloy forms an extruded structure.  
     
     
         48 . The component according to  claim 41 , wherein said alloy forms an automotive part selected from the group consisting of frames, support members, cross-members, instrument panel beams, roof rails, engine cradles, transfer cases, and steering components.  
     
     
         49 . The component according to  claim 41 , wherein said alloy forms a structure by one or more metal forming processes selected from the group consisting of bending, extruding, rolling, hydroforming, stamping, superplastic forming, gas forming, electromagnetic forming, and combinations thereof.  
     
     
         50 . A magnesium-based wrought alloy having a composition comprising: 
 aluminum (Al) of between about 2.5 to about 4.0 wt. %; manganese (Mn) and zinc (Zn) collectively present at less than about 1.0 wt. %; impurities collectively less than about 0.1 wt. %; and a balance of magnesium (Mg); wherein the wrought alloy has an elongation of greater than 8% at room temperature.    
     
     
         51 . The magnesium based alloy according to  claim 50 , wherein the wrought alloy has a yield strength greater than about 165 MPa.  
     
     
         52 . The magnesium based alloy according to  claim 50 , wherein the wrought alloy has an ultimate tensile strength of greater than about 230 MPa.  
     
     
         53 . A magnesium-based wrought alloy having a composition comprising: 
 aluminum (Al) of between about 2.5 to about 4.0 wt. %; manganese (Mn) and zinc (Zn) collectively present at less than about 1.0 wt. %; impurities collectively less than about 0.1 wt. %; and a balance of magnesium (Mg); wherein the wrought alloy having an extrusion speed of greater than 305 mm per minute at 360° C.    
     
     
         54 . The magnesium based alloy according to  claim 53 , wherein the wrought alloy has a yield strength greater than about 165 MPa.  
     
     
         55 . The magnesium based alloy according to  claim 53  above, wherein the wrought alloy has an ultimate tensile strength of greater than about 230 MPa.