Method for dissolvable aluminum alloys

Abstract

The method for equal channel angular extrusion increases yield strength and ultimate tensile strength of a dissolvable aluminum alloy. A billet of a dissolvable aluminum alloy is wrapped with a sheet cover so as to form a wrapped billet. The wrapped billet is extruded through an equal channel angular extrusion die with an extrusion angle ranging 90-135 degrees so as to form an extruded billet. The step of extruding is at a temperature ranging 150-250 degrees C., an extrusion rate ranging 0.003-0.010 inches per second, and a back pressure ranging 200-10000 psi. The dissolvable aluminum alloy of the extruded billet has a yield strength and ultimate tensile strength 50% greater than the initial yield strength and initial ultimate tensile strength.

We claim: 
     
         1 . A method for equal channel angular extrusion, comprising the steps of:
 wrapping a billet with a sheet cover so as to form a wrapped billet, said billet being comprised of a dissolvable aluminum alloy with an initial tensile yield strength; and   extruding said wrapped billet through an equal channel angular extrusion die with an extrusion angle ranging 90-135 degrees so as to form an extruded billet,   
       wherein the step of extruding is at a temperature ranging 150-250 degrees C., 
       wherein the step of extruding is at an extrusion rate ranging 0.003-0.010 inches per second, 
       wherein the step of extruding is at a back pressure ranging 200-10000 psi, and 
       wherein said extruded billet has an extruded tensile yield strength 50% greater than said initial tensile yield strength. 
     
     
         2 . The method of  claim 1 , wherein said temperature is 200 degrees C. 
     
     
         3 . The method of  claim 1 , wherein said extrusion rate is 0.005 inches per second. 
     
     
         4 . The method of  claim 1 , wherein said back pressure is 8000 psi. 
     
     
         5 . The method of  claim 1 , wherein said sheet cover is comprised of one of a group consisting of brass and graphite. 
     
     
         6 . A method for equal channel angular extrusion, comprising the steps of:
 wrapping a billet with a sheet cover so as to form a wrapped billet, said billet being comprised of a dissolvable aluminum alloy with an initial tensile ultimate strength; and   extruding said wrapped billet through an equal channel angular extrusion die with an extrusion angle ranging 90-135 degrees so as to form an extruded billet,   
       wherein the step of extruding is at a temperature ranging 150-250 degrees C., 
       wherein the step of extruding is at an extrusion rate ranging 0.003-0.010 inches per second, 
       wherein the step of extruding is at a back pressure ranging 200-10000 psi, and 
       wherein said extruded billet has an extruded tensile ultimate strength 50% greater than said initial tensile ultimate strength. 
     
     
         7 . The method of  claim 6 , wherein said temperature is 200 degrees C. 
     
     
         8 . The method of  claim 6 , wherein said extrusion rate is 0.005 inches per second. 
     
     
         9 . The method of  claim 6 , wherein said back pressure is 8000 psi. 
     
     
         10 . The method of  claim 6 , wherein said sheet cover is comprised of one of a group consisting of brass and graphite. 
     
     
         11 . A method for equal channel angular extrusion, comprising the steps of:
 wrapping a billet with a sheet cover so as to form a wrapped billet, said billet being comprised of a dissolvable aluminum alloy with an initial tensile elongation; and   extruding said wrapped billet through an equal channel angular extrusion die with an extrusion angle ranging 90-135 degrees so as to form an extruded billet,   
       wherein the step of extruding is at a temperature ranging 150-250 degrees C., 
       wherein the step of extruding is at an extrusion rate ranging 0.003-0.010 inches per second, 
       wherein the step of extruding is at a back pressure ranging 200-10000 psi, and 
       wherein said extruded billet has an extruded tensile elongation 50% greater than said initial tensile elongation. 
     
     
         12 . The method of  claim 11 , wherein said temperature is 200 degrees C. 
     
     
         13 . The method of  claim 11 , wherein said extrusion rate is 0.005 inches per second. 
     
     
         14 . The method of  claim 11 , wherein said back pressure is 8000 psi. 
     
     
         15 . The method of  claim 11 , wherein said sheet cover is comprised of one of group consisting of brass and graphite.