Magnesium alloy sheet material

Abstract

Disclosed is a magnesium alloy material having excellent tensile strength and favorable ductility. Therefore, the magnesium alloy sheet material formed by rolling a magnesium alloy having a long period stacking order phase crystallized at the time of casting includes in a case where a sheet-thickness traverse section of an alloy structure is observed at a substantially right angle to the longitudinal direction by a scanning electron microscope, a structure mainly composed of the long period stacking order phase, in which at least two or more αMg phases having thickness in the observed section of 0.5 μm or less are laminated in a layered manner with the sheet-shape long period stacking order phase.

1 . A magnesium alloy sheet material formed by rolling a magnesium alloy having a long period stacking order phase crystallized at the time of casting, comprising:
 in a case where a sheet-thickness traverse section of an alloy structure is observed at a substantially right angle to the longitudinal direction by a scanning electro microscope,   a structure mainly composed of the long period stacking order phase, in which at least two or more αMg phases having thickness in the observed section of 0.5 μm or less are laminated in a layered manner with the sheet-shape long period stacking order phase.   
     
     
         2 .- 7 . (canceled) 
     
     
         8 . The magnesium alloy sheet material according to  claim 1 , comprising 2 atom % of Zn, 2 atom % of Y, and the remaining part including Mg and unavoidable impurities. 
     
     
         9 . The magnesium alloy sheet material according to  claim 1 , wherein regarding the structure mainly composed of the long period stacking order phase, in a case where a section cut in the sheet thickness direction along the rolling direction of the magnesium alloy sheet material is observed from the perpendicular direction of the section, a range of an area ratio of the long period stacking order phase is 36% or more. 
     
     
         10 . The magnesium alloy sheet material according to  claim 1 , wherein the long period stacking order phase in the laminated structure has maximum thickness in the observed section of 9 μm or less. 
     
     
         11 . The magnesium alloy sheet material according to  claim 1 , wherein in the laminated structure, the sheet-shape long period stacking order phase and the αMg phases having smaller-thickness in the observed section than the long period stacking order phase are laminated in a layered manner. 
     
     
         12 . The magnesium alloy sheet material according to  claim 1 , wherein the sheet-shape long period stacking order phase in the laminated structure has minimum thickness in the observed section of 0.25 μm or more. 
     
     
         13 . The magnesium alloy sheet material according to  claim 1 , wherein the laminated structure includes an intermetallic compound. 
     
     
         14 . The magnesium alloy sheet material according to  claim 1 , wherein at least part of the laminated structure is shear-deformed or compression-deformed. 
     
     
         15 . The magnesium alloy sheet material according to  claim 1 , wherein at least part of the laminated structure is curved or bent.