Calcium-bearing magnesium and rare earth element alloy and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-11286544-B2
Application number	US-201716471168-A
Country	US
Kind code	B2
Filing date	Sep 11, 2017
Priority date	Jan 11, 2017
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

A calcium-bearing magnesium and rare earth element alloy consists essentially of, in mass percent, zinc (Zn): 1-3%; aluminum (Al): 1-3%; calcium (Ca): 0.1-0.4%; gadolinium (Gd): 0.1-0.4%; yttrium (Y): 0-0.4%; manganese (Mn): 0-0.2%; and balance magnesium (Mg).

First claim

What is claimed is:

1. A method for manufacturing a magnesium alloy sheet comprising:
weighting raw materials to obtain a desired composition;
charging said raw materials into a vacuum induction melting furnace to obtain a molten mass;
casting said molten mass to yield a magnesium alloy ingot consisting essentially of: about 1 to about 3 percent by weight zinc; about 1 to about 3 percent by weight aluminum; about 0.1 to about 0.4 percent by weight calcium; about 0.1 to about 0.4 percent by weight gadolinium; zero to about 0.4 percent by weight yttrium; zero to about 0.2 percent by weight manganese; and balance magnesium;
solid solution treating said magnesium alloy ingot to yield a treated magnesium alloy ingot;
hot rolling said treated magnesium alloy ingot to yield a rolled material;
cutting defects from said rolled material to obtain said magnesium alloy sheet; and
annealing said magnesium alloy sheet,
wherein the magnesium alloy sheet has a tensile strength of at least 245.0 MPa, an elongation to failure of at least 18.0%, and an IE value of at least 4.50.

2. The method of claim 1 , wherein said raw materials comprise:
a magnesium ingot of no less than 99.99 mass percent purity;
an aluminum ingot of no less than 99.9 mass percent purity;
a zinc ingot of no less than 99.99 mass percent purity;
a master alloy of magnesium and calcium;
a master alloy of magnesium and gadolinium;
optionally, a master alloy of magnesium and yttrium; and
optionally, a master alloy of magnesium and manganese.

3. The method of claim 1 , wherein said charging comprises heating said raw materials to at least 750° C. for about 10 to about 15 minutes.

4. The method of claim 1 , further comprising, prior to said casting, stirring said molten mass for about 5 to about 10 minutes, wherein said stirring comprises at least one of electromagnetic stirring, mechanical stirring and gas stirring.

5. The method of claim 1 , wherein said solid solution treating comprises maintaining said magnesium alloy ingot at a temperature of about 300 to about 450° C. for about 12 to about 24 hours, and then air-cooling to room temperature.

6. The method of claim 1 , wherein said hot rolling is performed at a temperature of about 400 to about 450° C. in multiple passes, wherein said hot rolling achieves a total reduction in thickness of about 90 percent, wherein thickness reductions within about 15 percent are achieved during first two passes of said multiple passes, wherein thickness reductions within about 8 to about 18 percent are achieved during last two passes of said multiple passes, and wherein thickness reductions within about 10 to about 30 percent are achieved during other passes of said multiple passes.

7. The method of claim 1 , further comprising extruding said treated magnesium alloy ingot prior to said hot rolling.

8. The method of claim 7 , wherein said extruding comprises extruding said treated magnesium alloy ingot at about 250 to about 350° C. into one of a plate having a thickness of about 5 to about 20 mm and a rod having a diameter of about 20 to about 25 mm, wherein the extrusion ratio is about 16 to about 23 to 1, and the extrusion rate is about 0.5 to about 3 mm/s.

9. The method of claim 8 , wherein said hot rolling is performed at a temperature of about 400 to about 450° C. in multiple passes, wherein said hot rolling achieves a sheet having a thickness of about 1 mm, wherein thickness reductions within about 20 percent are achieved during first two passes of said multiple passes, wherein thickness reductions within about 10 to about 25 percent are achieved during last two passes of said multiple passes, and wherein thickness reductions within about 15 to about 35 percent are achieved during other passes of said multiple passes.

10. The method of claim 1 , further comprising isothermal forging said treated magnesium alloy ingot prior to said hot rolling.

11. The method of claim 10 , wherein said isothermal forging is performed at a temperature of about 300 to about 350° C. and a forging rate of about 1 to about 3 mm/s to yield a thin round billet and a total reduction in thickness of about 75 to about 85 percent.

12. The method of claim 11 , wherein said hot rolling is performed at a temperature of about 400 to about 450° C. in multiple passes, wherein said hot rolling achieves a thin plate having a thickness of about 1 mm, wherein thickness reductions within about 20 percent are achieved during first two passes of said multiple passes, wherein thickness reductions within about 10 to about 25 percent are achieved during last two passes of said multiple passes, and wherein thickness reductions within about 15 to about 35 percent are achieved during other passes of said multiple passes.

13. The method of claim 1 , wherein said annealing comprising maintaining said alloy sheet at a temperature of about 350° C. for about 30 to about 60 minutes.

14. The method of claim 1 , wherein said yttrium is present at a non-zero quantity.

15. The method of claim 1 , wherein said manganese is present at a non-zero quantity.

16. The method of claim 1 , wherein:
said zinc is present at about 1 to about 2 percent by weight;
said aluminum is present at about 1 to about 2 percent by weight;
said calcium is present at about 0.1 to about 0.2 percent by weight;
said gadolinium is present at about 0.1 to about 0.2 percent by weight;
said yttrium is present at about 0 to about 0.2 percent by weight; and
said manganese is present at about 0 to about 0.2 percent by weight.

17. The method of claim 1 , further comprising forming the magnesium alloy sheet at room temperature.

18. A method for manufacturing a magnesium alloy sheet comprising:
forming the magnesium alloy sheet at room temperature, the magnesium alloy sheet consisting essentially of: about 1 to about 3 percent by weight zinc; about 1 to about 3 percent by weight aluminum; about 0.1 to about 0.4 percent by weight calcium; about 0.1 to about 0.4 percent by weight gadolinium; zero to about 0.4 percent by weight yttrium; zero to about 0.2 percent by weight manganese; and balance magnesium,
wherein the magnesium alloy sheet has a tensile strength of at least 245.0 MPa, an elongation to failure of at least 18.0%, and an IE value of at least 4.50.

19. The method of claim 18 , wherein:
said zinc is present at about 1 to about 2 percent by weight;
said aluminum is present at about 1 to about 2 percent by weight;
said calcium is present at about 0.1 to about 0.2 percent by weight;
said gadolinium is present at about 0.1 to about 0.2 percent by weight;
said yttrium is present at about 0 to about 0.2 percent by weight; and
said manganese is present at about 0 to about 0.2 percent by weight.

20. The method of claim 18 , wherein the magnesium alloy sheet has an elongation to failure of at least 24.0%.

Assignees

• Boeing Co

Inventors

• Jiang Haitao
• Kang Qiang
• Zhang Yun
• Liu Peng
• Dong Peng
• Xu Zhe
• Liu Chaomin

Classifications

• C22C1/03

  using master alloys · CPC title

• B21J1/02

  Preliminary treatment of metal stock without particular shaping, e.g. salvaging segregated zones, forging or pressing in the rough (modifying the physical properties by deformation C21D7/00, C22F1/00) · CPC title

• C22C23/04

  with zinc or cadmium as the next major constituent · CPC title

• B21B27/024

  Rolls for bars, rods, rounds, tubes, wire or the like · CPC title

• C22F1/06

  of magnesium or alloys based thereon · CPC title