| 摘要 |
A magnesium alloy sheet having good press formability, a magnesium alloy structural member produced by pressing the sheet, and a method for producing a magnesium alloy sheet are provided. The magnesium alloy sheet is composed of a magnesium alloy containing Al and Mn. When a region from a surface of the alloy sheet to 30% of the thickness of the alloy sheet in a thickness direction of the magnesium alloy sheet is defined as a surface region and when a 200 μm2 sub-region is arbitrarily selected from this surface region, the number precipitated impurity grains containing both Al and Mg and having a maximum diameter of 0.5 to 5 μm is 5 or less. When a 50 μm2 sub-region is arbitrarily selected from the surface region, the number of crystallized impurity grains containing both Al and Mn and having a maximum diameter of 0.1 to 1 μm is 15 or less. In the grains of the crystallized phases, the mass ratio Al/Mn of Al to Mn is 2 to 5. The magnesium alloy sheet has good press formability since the crystallized phases and precipitates that cause breaking are small in amounts contained and in size. |
| 主权项 |
1. A magnesium alloy structural member produced by press-forming a magnesium alloy sheet, wherein the press-forming is conducted at a temperature in a range from 200° C. to 280° C., a heat treatment or an anti-corrosion treatment is conducted after the press-forming, and the magnesium alloy is in a temperature range of 150° C. to 250° C. for 60 minutes or less, including the heat treatment,
the magnesium alloy sheet comprising: a magnesium alloy containing Al and Mn, wherein: when a region from a surface of the alloy sheet to 30% of the thickness of the alloy sheet in a thickness direction of the magnesium alloy sheet is defined as a surface region and when a 200 μm2 sub-region is arbitrarily selected from this surface region, the number of grains that are precipitates containing both Al and Mg and having a maximum diameter of 0.5 to 5 μm is 5 or less, when a 50 μm2 sub-region is arbitrarily selected from the surface region, the number of grains that are crystallized phases containing both Al and Mn and having a maximum diameter of 0.1 to 1 μm is 15 or less, in the grains of the crystallized phases, the mass ratio Al/Mn of Al to Mn is 2 to 5, the magnesium alloy contains 5% by mass to 12% by mass of Al and 0.1% by mass to 2.0% by mass of Mn, the magnesium alloy contains at least one element selected from the group consisting of Zn, Si, Ca, Sr, Y, Cu, Ag, Ce, Zr, and rare earth elements, excluding Y and Ce, and the magnesium alloy includes precipitates consisting of Mg17Al12. |
