Method for improving mouldability of magnesium-alloy sheet material, and magnesium-alloy sheet material produced thereby

Abstract

A method for increasing formability of magnesium alloy sheet and the magnesium alloy sheet prepared by the same are provided, in which the method includes the following steps: forming {10-12} twins in magnesium alloy sheet (step 1); and annealing the magnesium alloy sheet of step 1 (step 2). The present invention also provides the magnesium alloy sheet containing {10-12} twins prepared by the method. Accordingly, the room temperature formability and the warm formability are increased by forming {10-12} twins through deformation on the magnesium alloy sheet and subsequently performing annealing, because it is possible to artificially form {10-12} twins without increasing dislocations in the magnesium alloy sheet and accommodate the deformation generated during the forming via annihilation of the twins.

We claim: 
     
         1 . A method for increasing formability of magnesium alloy sheet comprising the following steps:
 forming {10-12} twins in magnesium alloy sheet (step 1); and   annealing the magnesium alloy sheet of step 1 (step 2), wherein the magnesium alloy sheet comprises {10-12} twins present after the annealing and reduced dislocations than before the annealing.   
     
     
         2 . The method for increasing formability of magnesium alloy sheet according to  claim 1 , wherein the forming of the {10-12} twins in step 1 causes texture to develop, in which basal planes are aligned perpendicular to the rolling direction. 
     
     
         3 . The method for increasing formability of magnesium alloy sheet according to  claim 1 , wherein the step 1 is performed by applying compressive deformation to the magnesium alloy sheet. 
     
     
         4 . The method for increasing formability of magnesium alloy sheet according to  claim 3 , wherein the compressive deformation is applied to the direction parallel to the rolling plane of the magnesium alloy sheet. 
     
     
         5 . The method for increasing formability of magnesium alloy sheet according to  claim 3 , wherein the amount of compressive deformation is 1˜15%. 
     
     
         6 . The method for increasing formability of magnesium alloy sheet according to  claim 1 , wherein the annealing is performed at 200˜550° C. for 10˜480 minutes. 
     
     
         7 . The method for increasing formability of magnesium alloy sheet according to  claim 6 , wherein the annealing is performed at 350˜500° C. for 60˜240 minutes. 
     
     
         8 . A magnesium alloy sheet with increased formability, which is prepared by the method according to  claim 1  and comprises the {10-12} twins.