Methods for extruding coarse-grained, low aluminum content magnesium alloys

Patent metadata

Field	Value
Publication number	US-12226815-B2
Application number	US-202217872766-A
Country	US
Kind code	B2
Filing date	Jul 25, 2022
Priority date	May 27, 2022
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

The present disclosure provides a method of forming an extruded billet from a coarse-grained magnesium alloy billet. The method includes extruding the coarse-grained magnesium alloy biller at temperatures greater than or equal to about 300° C. to less than or equal to about 360° C. to from the extruded billet. The coarse-grained magnesium alloy billet has an average grain size greater than or equal to about 800 μm, and has a low aluminum content. The coarse-grained magnesium alloy billet includes greater than or equal to about 0.5 wt. % to less than or equal to about 3 wt. % of aluminum. The extruded billet may have a plurality of twins with lenticular morphology, which occupies an area fraction greater than or equal to about 20% of a total area of the extruded billet.

First claim

What is claimed is:

1. A method of forming an extruded billet from a coarse-grained magnesium alloy billet, the method comprising:
extruding the coarse-grained magnesium alloy billet at temperatures less than or equal to about 360° C. to form the extruded billet, the coarse-grained magnesium alloy billet having an average grain size greater than or equal to about 800 micrometers (μm) and comprising a plurality of twins with lenticular morphology.

2. The method of claim 1 , wherein the coarse-grained magnesium alloy billet is extruded at temperatures greater than or equal to about 300° C.

3. The method of claim 1 , wherein the coarse-grained magnesium alloy billet has a low aluminum content and comprises greater than or equal to about 1.5 wt. % to less than or equal to about 3 wt. % of aluminum.

4. The method of claim 3 , wherein the coarse-grained magnesium alloy billet comprises about 2 wt. % of aluminum.

5. The method of claim 3 , wherein the coarse-grained magnesium alloy billet further comprises greater than or equal to about 0.3 wt. % to less than or equal to about 0.6 wt. % of manganese.

6. The method of claim 5 , wherein the coarse-grained magnesium alloy billet comprises about 0.5 wt. % of manganese.

7. The method of claim 3 , wherein the coarse-grained magnesium alloy billet further comprises at least one of:
greater than 0 wt. % to less than or equal to about 3 wt. % of zinc;
greater than 0 wt. % to less than or equal to about 3 wt. % of tin;
greater than 0 wt. % to less than or equal to about 0.5 wt. % of calcium; and
greater than 0 wt. % to less than or equal to about 5 wt. % of rare earth metals.

8. The method of claim 7 , wherein the coarse-grained magnesium alloy billet comprises about 1 wt. % of zinc.

9. The method of claim 1 , wherein the plurality of twins occupy an area fraction greater than or equal to about 20% of a total area of the billet.

10. A method of forming a forged component, the method comprising:
forging an extruded billet to form the forged component, the extruded billet prepared from a coarse-grained magnesium alloy billet by extruding the coarse-grained magnesium alloy billet at temperatures less than or equal to about 360° C. to form the extruded billet, the coarse-grained magnesium alloy billet having an average grain size greater than or equal to about 800 micrometers (μm) and comprising:
greater than or equal to about 0.3 wt. % to less than or equal to about 0.6 wt. % of manganese;
greater than or equal to about 0 wt. % to less than or equal to about 3 wt. % of zinc;
greater than or equal to about 0 wt. % to less than or equal to about 3 wt. % of tin;
greater than or equal to about 0 wt. % to less than or equal to about 0.5 wt. % of calcium; and
greater than or equal to about 0 wt. % to less than or equal to about 5 wt. % of rare earth metals.

11. The method of claim 10 , wherein the forging comprises moving the extruded billet through a forging die having an opening that corresponds to a desired cross-sectional geometry of the forged component.

12. The method of claim 10 , wherein the extruding is conducted at temperatures greater than or equal to about 300° C.

13. The method of claim 10 , wherein the coarse-grained magnesium alloy billet comprises greater than or equal to about 1.5 wt. % to less than or equal to about 3 wt. % of aluminum.

14. The method of claim 10 , wherein the forged component comprises a plurality of twin-induced dynamic recrystallization grains, the twin-induced dynamic recrystallization grains occupying an area fraction greater than or equal to about 20% of a total area of the forged component.

15. The method of claim 14 , wherein the forged component comprises greater than or equal to about 20% of boundaries with misorientations of greater than or equal to about 60 degrees to less than or equal to about 100 degrees.

16. A method of forming an extruded billet from a coarse-grained magnesium alloy billet, the method comprising:
moving the coarse-grained magnesium alloy billet through an extruding die at temperatures greater than or equal to about 300° C. to less than or equal to about 360° C. to form the extruded billet, the coarse-grained magnesium alloy billet comprising greater than or equal to about 0.5 wt. % to less than or equal to about 3 wt. % of aluminum and having an average grain size greater than or equal to about 800 micrometers (μm), and the extruded billet comprising a plurality of twins with lenticular morphology, the plurality of twins with lenticular morphology occupying an area fraction greater than or equal to about 20% of a total area of the extruded billet.

17. The method of claim 16 , wherein the coarse-grained magnesium alloy further comprises:
greater than or equal to about 0.3 wt. % to less than or equal to about 0.6 wt. % of manganese.

18. The method of claim 16 , wherein the coarse-grained magnesium alloy further comprises at least one of:
greater than 0 wt. % to less than or equal to about 3 wt. % of zinc;
greater than 0 wt. % to less than or equal to about 3 wt. % of tin;
greater than 0 wt. % to less than or equal to about 0.5 wt. % of calcium; and
greater than 0 wt. % to less than or equal to about 5 wt. % of rare earth metals.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Zhan Henry
• Wang Congjie

Classifications

• C22C23/02

  with aluminium as the next major constituent · CPC title

• B21C23/001

  to improve the material properties, e.g. lateral extrusion · CPC title

• C22C23/00

  Alloys based on magnesium · CPC title

• C22F1/06 Primary

  of magnesium or alloys based thereon · CPC title

• B21C23/002 Primary

  Extruding materials of special alloys so far as the composition of the alloy requires or permits special extruding methods of sequences · CPC title