Asymmetric extrusion method and apparatus

Abstract

An asymmetric extrusion method, an extruded material extruded using the same, a die for asymmetric extrusion, and an asymmetric extrusion apparatus. According to the asymmetric extrusion method, an extruded material having a plate shape is formed by pushing an extruding material through a die including an extrusion hole having an asymmetric shape with respect to an extrusion direction of the extruding material, so as to extrude the extruding material while inducing shear strain in the extruding material.

1 - 20 . (canceled) 
     
     
         21 . An asymmetric extrusion method for extruding an extruding material to a plate shape, the method comprising:
 pushing the extruding material through a die comprising an extrusion hole having an asymmetric shape with respect to an extrusion direction of the extruding material, so as to extrude the extruding material while inducing shear strain in a thickness direction of the extruding material,   wherein the extruding material is a metal or a metal alloy.   
     
     
         22 . The asymmetric extrusion method of  claim 21 , wherein the extrusion hole of the die comprises a tapered part having a width varied according to the extrusion direction of the extruding material, and
 wherein the tapered part has an asymmetric shape with respect to the extrusion direction of the extruding material.   
     
     
         23 . The asymmetric extrusion method of  claim 22 , wherein the tapered part has an asymmetric shape with respect to a plate surface direction of the plate shape. 
     
     
         24 . The asymmetric extrusion method of  claim 22 , wherein the die comprises a pair of first inner surfaces spaced apart from each other at the tapered part along the thickness direction of the plate shape, and
 wherein the pair of first inner surfaces have different gradients along the extrusion direction.   
     
     
         25 . The asymmetric extrusion method of  claim 24 , wherein one of the pair of first inner surfaces is parallel to the extrusion direction. 
     
     
         26 . The asymmetric extrusion method of  claim 24 , wherein the extrusion hole has a rectangular cross-section,
 wherein the die comprises a pair of second inner surfaces spaced apart from each other at the tapered part along a width direction of the plate shape, and   wherein the pair of second inner surfaces are symmetric along the extrusion direction.   
     
     
         27 . The asymmetric extrusion method of  claim 26 , wherein the pair of second inner surfaces are parallel to the extrusion direction. 
     
     
         28 . The asymmetric extrusion method of  claim 21 , wherein the shear strain tilts a basal plane slip system of the extruding material with respect to a surface of the sheet. 
     
     
         29 . The asymmetric extrusion method of  claim 21 , wherein the extruding material is pushed at room temperature.