Hydrostatic cyclic expansion extrusion process for producing ultrafine-grained rods

Abstract

A method of producing ultrafine-grained materials and a system for mass production of ultrafine-grained materials is disclosed. The system includes a die assembly with a die channel that extends from a first end to a second end. The system also includes first punch and a second punch. A lubricant is poured into a portion of the die channel to surround a workpiece that is positioned within the die channel in order to minimize the effects of friction during processing.

1 . A method of producing ultrafine grain materials comprising:
 positioning a workpiece in a die channel, the die channel being formed in a die assembly;   pouring lubricant into a first end of the die channel, thereby substantially surrounding the workpiece with the lubricant; and   moving a first punch toward the workpiece and thereby pushing the workpiece toward a second end of the die channel.   
     
     
         2 . The method according to  claim 1 , further comprising inserting a first seal into the first end of the die channel, thereby sealing the lubricant in the die channel. 
     
     
         3 . The method according to  claim 1 , further comprising inserting the first punch into the first end of the die channel. 
     
     
         4 . The method according to  claim 3 , further comprising inserting a second punch into the second end of the die channel. 
     
     
         5 . The method according to  claim 2 , further comprising rotating the die assembly approximately 180 degrees to complete a first pass. 
     
     
         6 . The method according to  claim 5 , further comprising pouring additional lubricant into the second end of the die channel during a second pass. 
     
     
         7 . The method according to  claim 6 , further comprising inserting a second seal into the second end of the die channel during the second pass. 
     
     
         8 . The method according to  claim 7 , further comprising inserting the first punch into the second end of the die channel. 
     
     
         9 . The method according to  claim 4 , further comprising removing the second punch from the die assembly. 
     
     
         10 . The method according to  claim 7 , further comprising removing the first seal from the die assembly. 
     
     
         11 . A die assembly for production of ultrafine-grain materials comprising:
 a first die segment including a first die portion joined to a first panel portion;   a second die segment including second die portion joined to a second panel portion; and   the first die segment being removably attached to the second die segment.   
     
     
         12 . The die assembly of  claim 11 , further comprising a first plurality of fasteners configured to attach the first die portion to the first panel portion. 
     
     
         13 . The die assembly of  claim 11 , wherein the first panel portion comprises a gasket. 
     
     
         14 . The die assembly of  claim 11 , wherein the first die portion has a substantially cylindrical shape. 
     
     
         15 . The die assembly of  claim 14 , wherein the second die portion has a substantially cylindrical shape. 
     
     
         16 . The die assembly of  claim 11 , wherein the first die portion and the first panel portion include a plurality of apertures for receiving the first plurality of fasteners. 
     
     
         17 . The die assembly of  claim 11 , further comprising a set of connectors configured to removably attach the first die segment to the second die segment. 
     
     
         18 . The die assembly of  claim 11 , further comprising a die channel extending from the first die segment to the second die segment. 
     
     
         19 . The die assembly of  claim 18 , wherein the die channel includes an expansion section and an extrusion section. 
     
     
         20 . The die assembly of  claim 12 , further comprising a second plurality of fasteners configured to attach the second die portion to the second panel portion. 
     
     
         21 . (canceled) 
     
     
         22 . (canceled)