MAGNESIUM ALLOY SHEET AND MANUFACTURING METHOD THEREFOR

1 . A magnesium alloy sheet comprising:

0.1 to 1.5 wt % of Zn, 0.08 to 0.7 wt % of Gd, a remainder of Mg, and other inevitable impurities with respect to an entire 100 wt % of the magnesium alloy sheet,

wherein the magnesium alloy sheet satisfies Relational Expression 1:

[Zn]/[Gd]≥3.0  [Relational Expression 1]

wherein the [Zn] and [Gd] indicate wt % of each component.

2 . The magnesium alloy sheet of claim 1 , wherein

the magnesium alloy sheet satisfies Relational Expression 2:

15.0≥[Zn]/[Gd]≥3.0  [Relational Expression 2]

wherein the [Zn] and [Gd] indicate wt % of each component.

3 . The magnesium alloy sheet of claim 2 , wherein

the magnesium alloy sheet satisfies Relational Expression 3:

13.0≥[Zn]/[Gd]≥3.0  [Relational Expression 3]

wherein the [Zn] and [Gd] indicate wt % of each component.

4 . The magnesium alloy sheet of claim 3 , further comprising

0.3 wt % or less of Mn (excluding 0 wt %) with respect to the total of 100 wt % of the magnesium alloy sheet.

5 . The magnesium alloy sheet of claim 4 , wherein

the magnesium alloy sheet comprises a secondary phase, and

the number of secondary phases per an area of 40000 μm 2 of the magnesium alloy plate is 1 to 20.

6 . The magnesium alloy sheet of claim 5 , wherein

the magnesium alloy sheet comprises a secondary phase, and

the average particle diameter of the secondary phase is 0.1 to 3 μm.

7 . The magnesium alloy sheet of claim 6 , wherein

an average crystal grain size of the magnesium alloy sheet is 5 to 30 μm.

8 . The magnesium alloy sheet of claim 7 , wherein

the limited dome height (LDH) of the magnesium alloy sheet is 10.5 mm or more.

9 . The magnesium alloy sheet of claim 8 , wherein

an edge crack of the magnesium alloy sheet is 5 mm or less.

10 . The magnesium alloy sheet of claim 9 , wherein

the magnesium alloy plate has a maximum texture intensity of 4.5 or less with respect to the (0001) plane.

11 . A method for manufacturing a magnesium alloy sheet, comprising:

preparing a casting material by casting an alloy melt solution comprising 0.1 to 1.5 wt % of Zn, 0.08 to 0.7 wt % of Gd, a remainder of Mg, and other inevitable impurities for the entire 100 wt %;

homogenizing and heat-treating the casting material;

preparing a rolled material by rolling the homogenized and heat-treated casting material; and

finally annealing the rolled material,

wherein the alloy melt solution satisfies Relational Expression 4:

[Zn]/[Gd]≥3.0  [Relational Expression 4]

wherein the [Zn] and [Gd] indicate wt % of each component.

12 . The method of claim 11 , wherein

the alloy melt solution satisfies Relational Expression 5:

15.0≥[Zn]/[Gd]≥3.0  [Relational Expression 5]

wherein the [Zn] and [Gd] indicate wt % of each component.

13 . The method of claim 12 , wherein

the alloy melt solution satisfies Relational Expression 6:

13.0≥[Zn]/[Gd]≥3.0  [Relational Expression 6]

wherein the [Zn] and [Gd] indicate wt % of each component.

14 . The method of claim 11 , wherein

the alloy melt solution further comprises 0.3 wt % or less of Mn (excluding 0 wt %) with respect to the total of 100 wt % of the magnesium alloy sheet.

15 . The method of claim 11 , wherein

the homogenizing and heat-treating of a casting material is performed at a temperature of 300 to 500° C.

16 . The method of claim 15 , wherein

the homogenizing and heat-treating of a casting material is performed for 5 hour or more.

17 . The method of claim 11 , wherein

the preparing of a rolled material comprises performing rolling at a temperature of 150 to 350° C.

18 . The method of claim 17 , wherein

the preparing of a rolled material comprises performing a rolling with a reduction ratio that is greater than 0 and equal to or less than 30% for each rolling.