Magnesium alloys and methods of making and use thereof

Abstract

Disclosed herein are magnesium alloys and methods of making and use thereof. The magnesium alloys comprise: from 1 to 1.5 wt. % Zn, from 1 to 1.4 wt. % Al, from 0.2 to 0.7 wt. % Ca, from 0.2 to 0.4 wt. % Ce, from 0.1 to 0.8 wt. % Mn, and the balance comprising Mg.

What is claimed is: 
     
         1 . A method of making a magnesium alloy based object comprising a magnesium alloy, the method comprising:
 heating an object comprising a preliminary magnesium alloy at a first temperature for a first amount of time;
 wherein the preliminary magnesium alloy comprises a first intermetallic phase having a melting temperature, a second intermetallic phase having a melting temperature, a third intermetallic phase having a melting temperature, and an alloy phase having a solidus temperature; 
 wherein the melting temperature of the first intermetallic phase is lower than the melting temperature of the second intermetallic phase, the melting temperature of the third intermetallic phase, and the solidus temperature of the alloy phase; 
 wherein the melting temperature of the second intermetallic phase is lower than the melting temperature of the third intermetallic phase and the solidus temperature of the alloy phase; 
 wherein the melting temperature of the third intermetallic phase is higher than the solidus temperature of the alloy phase; 
 wherein the first temperature is above the melting temperature of the first intermetallic phase, below the melting temperature of the second intermetallic phase, below the melting temperature of the third intermetallic phase, and below the solidus temperature of the alloy phase; 
 thereby substantially dissolving the first intermetallic phase into the alloy phase to form an object comprising a first intermediate magnesium alloy, the first intermediate magnesium alloy comprising the second intermetallic phase, the third intermetallic phase, and the alloy phase; 
   heating the object comprising the first intermediate magnesium alloy at a second temperature for a second amount of time;
 wherein the second temperature is above the melting temperature of the second intermetallic phase, below the melting temperature of the third intermetallic phase, and below the solidus temperature of the alloy phase; 
 thereby substantially dissolving the second intermetallic phase into the alloy phase to form an object comprising a second intermediate magnesium alloy, the second intermediate magnesium alloy comprising the third intermetallic phase and the alloy phase; and 
   heating the object comprising the second intermediate magnesium alloy at a third temperature for a third amount of time;
 wherein the third temperature is above the melting temperature of the third intermetallic phase; 
 thereby substantially dissolving the third intermetallic phase into the alloy phase and minimizing incipient melting of the alloy phase to form the magnesium alloy based object; 
   wherein the magnesium alloy comprises:
 from 1 to 1.5 wt. % Zn, 
 from 1 to 1.4 wt. % Al, 
 from 0.2 to 0.7 wt. % Ca, 
 from 0.2 to 0.4 wt. % Ce, 
 from 0.1 to 0.8 wt. % Mn, and 
 the balance comprising Mg. 
   
     
     
         2 . The method of  claim 1 , wherein the magnesium alloy comprises from 1 to 1.25 wt. % Zn, from 1 to 1.4 wt. % Al, from 0.2 to 0.45 wt. % Ca, from 0.2 to 0.4 wt. % Ce, from 0.1 to 0.8 wt. % Mn, and the balance comprising Mg. 
     
     
         3 . The method of  claim 1 , wherein the magnesium alloy comprises from 1 to 1.25 wt. % Zn, from 1 to 1.2 wt. % Al, from 0.2 to 0.45 wt. % Ca, from 0.2 to 0.3 wt. % Ce, from 0.2 to 0.6 wt. % Mn, and the balance comprising Mg. 
     
     
         4 . The method of  claim 1 , wherein the first temperature is from 10° C. to 200° C. above the melting temperature of the first intermetallic phase, wherein the first temperature is from 250° C. to 325° C., wherein the first amount of time is from 1 hour to 24 hours, or a combination thereof. 
     
     
         5 . The method of  claim 1 , wherein the second temperature is from 10° C. to 120° C. above the melting temperature of the second intermetallic phase, wherein the second temperature is from 325° C. to 450° C., wherein the second amount of time is from 1 hour to 24 hours, or a combination thereof. 
     
     
         6 . The method of  claim 1 , wherein the third temperature is from 10° C. to 50° C. above the melting temperature of the third intermetallic phase, wherein the third temperature is from 450° C. to 500° C., wherein the third amount of time is from 0.1 hours to 3 hours, or a combination thereof. 
     
     
         7 . The method of  claim 1 , wherein the first intermetallic phase comprises Al 4 Mn, Ca 2 Mg 5 Zn 5 , Al 11 Mn 4 , or a combination thereof. 
     
     
         8 . The method of  claim 1 , wherein the second intermetallic phase comprises Al 2 Ca. 
     
     
         9 . The method of  claim 1 , wherein the third intermetallic phase comprises AlCaMg. 
     
     
         10 . The method of  claim 1 , wherein the magnesium alloy based object comprises a substantially homogeneous matrix comprising the alloy phase. 
     
     
         11 . The method of  claim 1 , further comprising thermomechanically treating the magnesium alloy based object by heating the magnesium alloy based object at a fourth temperature for a fourth amount of time and, subsequently, mechanically treating the magnesium alloy based object, wherein the fourth temperature is above room temperature and below the solidus temperature. 
     
     
         12 . The method of  claim 11 , wherein mechanically treating the magnesium alloy based object comprises rolling the magnesium alloy based object, extrusion, and/or forging. 
     
     
         13 . A magnesium alloy based object made by the method of  claim 1 . 
     
     
         14 . The magnesium alloy based object of  claim 13 , wherein the magnesium alloy based object has a yield strength of 200 MPa or more, an elongation to failure of 25% or more, an Index Erichsen value of 6 mm or more at room temperature, an average grain size of from 5 μm to 14 μm, or a combination thereof. 
     
     
         15 . A method of use of the magnesium alloy based object of  claim 13 , the method comprising using the magnesium alloy based object in an automotive, aerospace, or electronic application. 
     
     
         16 . A method of use of a magnesium alloy, the method comprising using the magnesium alloy in an automotive, aerospace, or electronic application, wherein the magnesium alloy comprises:
 from 1 to 1.5 wt. % Zn,   from 1 to 1.4 wt. % Al,   from 0.2 to 0.7 wt. % Ca,   from 0.2 to 0.4 wt. % Ce,   from 0.1 to 0.8 wt. % Mn, and   the balance comprising Mg.   
     
     
         17 . The method of  claim 16 , wherein the magnesium alloy comprises from 1 to 1.25 wt. % Zn, from 1 to 1.4 wt. % Al, from 0.2 to 0.45 wt. % Ca, from 0.2 to 0.4 wt. % Ce, from 0.1 to 0.8 wt. % Mn, and the balance comprising Mg. 
     
     
         18 . The method of  claim 16 , wherein the magnesium alloy comprises from 1 to 1.25 wt. % Zn, from 1 to 1.2 wt. % Al, from 0.2 to 0.45 wt. % Ca, from 0.2 to 0.3 wt. % Ce, from 0.2 to 0.6 wt. % Mn, and the balance comprising Mg. 
     
     
         19 . The method of  claim 16 , wherein the Zn, Al, Ca, Ce, and Mn are substantially dissolved in the magnesium alloy. 
     
     
         20 . The method of  claim 16 , wherein the magnesium alloy is substantially free of Al 4 Mn, Ca 2 Mg 5 Zn 5 , Al 11 Mn 4 , Al 2 Ca, AlCaMg, or a combination thereof.