Cold-rolling method for a wrought mg alloy with weak/non-basal texture and a cold rolled sheet

Abstract

The present invention relates to a cold-rolling method for cold-rolling a wrought Mg alloy with a weak or non-basal texture as well as a cold-rolled sheet, the method comprising the steps of: pre-treating a billet of the wrought Mg alloy with a weak or non-basal texture, and then cold rolling it; wherein the weak or non-basal texture plane of said billet is selected as a rolling plane, and the rolling direction is parallel to the rolling plane; and said billet is cold rolled at room temperature to a sheet or foil with a thickness of 0.1 to 100 mm, wherein single-pass or multi-pass rolling is used, and the cold rolling is followed by an annealing at 200 to 400° C. for 10 min to 48 h.

1 . A cold-rolling method for cold-rolling a wrought Mg alloy with a weak/non-basal texture having a weak or non-basal texture plane, comprising the steps of:
 pre-treating a billet of the wrought Mg alloy with a weak or non-basal texture, and then cold rolling it in a rolling direction;   wherein the weak or non-basal texture plane of said billet is selected as a rolling plane, and the rolling direction is parallel to the rolling plane; and the thickness of said billet of the wrought Mg alloy with a weak or non-basal texture, perpendicular to the rolling plane, is in the range of 0.2 to 200 mm; and   when one of the planes of said billet is selected as a reference plane, wherein the maximum intensity of its ( 0002 ) pole figure is less than 6, or the position of the maximum intensity of its ( 0002 ) pole figure tilts no less than 25° from the normal direction of the reference plane, the selected plane is a weak or non-basal texture plane.   
     
     
         2 . The cold-rolling method of  claim 1 , wherein said wrought Mg alloys with a weak or non-basal texture is a Mg-RE or Mg-RE-Zn system alloy, which contains, by weight, 0.1 to 10% RE, 0 to 5% Zn, ≦1% Zr and/or ≦2% Mn, with Mg being the balance, wherein RE represents a rare earth metal. 
     
     
         3 . The cold-rolling method of  claim 1 , wherein RE is Gd, Y, or a mixture thereof. 
     
     
         4 . The cold-rolling method of  claim 1 , wherein the grain size of said billet of the wrought Mg alloy with a weak or non-basal texture is no more than 100 μm. 
     
     
         5 . The cold-rolling method of  claim 1 , wherein said billet is cold rolled to a sheet or foil with a thickness of 0.1 to 100 mm. 
     
     
         6 . The cold-rolling method of  claim 1 , wherein the cold rolling is a single-pass cold-rolling process, having a reduction in the range of 20% to 50%, and a rolling speed in the range of 1 to 50 m/min. 
     
     
         7 . The cold-rolling method of  claim 1 , wherein the cold rolling is a multi-pass cold-rolling process, having rolling passes in the range of 10 to 50, a reduction per pass in the range of 1 to 5%, a total reduction in the range of 40% to 80%, and a rolling speed in the range of 1 to 50 m/min. 
     
     
         8 . The cold-rolling method of  claim 1 , wherein the cold-rolled sheet or foil is optionally be annealed at 200 to 400° C. for 10 min to 48 h. 
     
     
         9 . The cold-rolling method of  claim 5 , wherein the cold-rolled sheet or foil is optionally be annealed at 200 to 400° C. for 10 min to 48 h. 
     
     
         10 . The cold-rolling method of  claim 6 , wherein the cold-rolled sheet or foil is optionally be annealed at 200 to 400° C. for 10 min to 48 h. 
     
     
         11 . A cold rolled sheet, of the wrought Mg alloy with a weak or non-basal texture, produced by the cold-rolling method of  claim 1 . 
     
     
         12 . The cold rolled sheet of  claim 11 , wherein compared with the billet of the wrought Mg alloy with a weak or non-basal texture for cold-rolling, the strength of the cold-rolled sheet is increased by no less than 15%, and
 compared with the billet of the wrought Mg alloy with a weak or non-basal texture for cold-rolling, the strength of the cold-rolled sheet after annealing treatment is increased by no less than 10%, and the elongation δ along the rolling direction is no less than 25%.