Systems and methods for implementing bulk metallic glass-based macroscale gears

Patent metadata

Field	Value
Publication number	US-11920668-B2
Application number	US-202117193573-A
Country	US
Kind code	B2
Filing date	Mar 5, 2021
Priority date	Jun 26, 2012
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

Systems and methods in accordance with embodiments of the invention implement bulk metallic glass-based macroscale gears. In one embodiment, a method of fabricating a bulk metallic glass-based macroscale gear, where at least either the thickness of the gear is greater than 3 mm or the diameter of the gear is greater than 9 mm, includes: obtaining design parameters of the gear to be formed; selecting a bulk metallic glass from which the gear will be formed based on the obtained design parameters, where the selected bulk metallic glass is characterized by a resistance to standard modes of wear and a resistance to brittle fracture such that a gear can be formed from the selected bulk metallic glass that accords with the obtained design parameters; and fabricating the gear from the selected bulk metallic glass that accords with the obtained design parameters.

First claim

What claimed is:

1. A method of fabricating a bulk metallic glass-based macroscale gear, comprising:
identifying an alloy system with a fracture toughness of between 20 MPa*m 1/2 and 100 MPa*m 1/2 ;
micro-alloying the alloy system to achieve a hardness of at least 400 Vickers, while maintaining the fracture toughness of between 20 MPa*m 1/2 and 80 MPa*m 1/2 , and a glass forming ability of 4 mm;
selecting a bulk metallic glass forming alloy from the micro-alloyed alloying system, wherein the bulk metallic glass forming alloy is characterized by a set of criteria comprising: a hardness of 450 to 565 Vickers, a fracture toughness of between 20 and 80 MPa*m 1/2 , a glass forming ability of at least 4 mm, and a plastic zone radius; and
fabricating the bulk metallic glass-based macroscale gear free of crystalline phase from the selected bulk metallic glass forming alloy, the gear having a plurality of gear teeth and characterized by a shape and a plurality of dimensions, wherein at least one dimension of the plurality of dimensions is larger than the plastic zone radius.

2. The method of claim 1 , wherein the hardness is between 500 and 565 Vickers.

3. The method of claim 1 , wherein the at least one dimension of the gear is selected from the group consisting of: a thickness, and a diameter.

4. The method of claim 3 , wherein the at least one dimension of the gear is the thickness, and the thickness is greater than 3 mm.

5. The method of claim 3 , wherein the at least one dimension of the gear is the diameter, and the diameter is greater than 5 mm.

6. The method of claim 1 , wherein the fracture toughness is between approximately 40 MPa*m 1/2 and 80 MPa*m 1/2 .

7. The method of claim 1 , wherein the hardness is at least 550 Vickers.

8. The method of claim 1 , wherein the hardness is between 500 and 565 Vickers, and the fracture toughness is between 40 MPa*m 1/2 and 80 MPa*m 1/2 .

9. The method of claim 1 , wherein the bulk metallic glass forming alloy is further characterized by one or more properties selected from the group consisting of: a wear volume loss of less than 2 mm 3 as determined in an ASTM pin-on-disk test setup that uses a steel wear ball 100 g weight, 1.2 km of total wear track, run at 200 rpm; Young's Modulus of between 90 and 115 GPa; density of between 4.5 and 6 g/cm 3 , and any combination thereof.

10. The method of claim 1 , wherein the bulk metallic glass forming alloy is an alloy based on an element selected from the group consisting of: Zr, Ti, Cu, Pd, and Pt.

11. The method of claim 10 , wherein the bulk metallic glass forming alloy is a TiZrBeX alloy, and further wherein X is one or more late transition metal element.

12. The method of claim 11 , wherein:
Ti is between approximately 30 and 60 atomic % of the TiZrBeX alloy;
Zr is between approximately 15 and 35 atomic % of the TiZrBeX alloy;
Be is between approximately 7 and 35 atomic % of the TiZrBeX alloy; and
all other constituent elements of the TiZrBeX alloy comprise less than approximately 20 atomic %.

13. The method of claim 1 , wherein the gear is configured to operate at a temperature distinct from room or near room temperature, and providing the bulk metallic glass forming alloy further comprises adjusting the set of criteria such that the fracture toughness is compensated for temperature dependent changes to optimize operating of the gear at the temperature.

14. The method of claim 13 , wherein the temperature is below 0° C., and providing the bulk metallic glass forming alloy further comprises adjusting the set of criteria such that the fracture toughness is extrapolated using a relationship of Charpy impact energy as a function of temperature.

15. The method of claim 14 , wherein extrapolating comprises correlating a desired threshold Charpy impact energy at the temperature with a threshold Charpy impact energy at room temperature using the relationship of Charpy impact energy as a function of temperature.

16. The method of claim 15 , wherein the relationship of Charpy impact energy as a function of temperature is linear.

17. The method of claim 16 , wherein the relationship of Charpy impact energy as a function of temperature is 0.02 J/° C.

18. The method of claim 1 , further comprising depositing a coating over at least a portion of the plurality of gear teeth, wherein the coating is a hard and/or wear-resistant coating.

19. The method of claim 18 , wherein the coating is a molybdenum-based alloy.

20. The method of claim 19 , wherein the coating is MoS 2 .

Assignees

• California Inst Of Techn

Inventors

• Hofmann Douglas C
• Kennett Andrew
• Boykins Kobie T

Classifications

• F16H55/06 Primary

  Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties · CPC title

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title

• C22C14/00

  Alloys based on titanium · CPC title

• C22C30/00

  Alloys containing less than 50% by weight of each constituent · CPC title

• C22C45/10

  with molybdenum, tungsten, niobium, tantalum, titanium, or zirconium {or Hf} as the major constituent · CPC title