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

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.

What claimed is: 
     
         1 . A method of fabricating a bulk metallic glass-based macroscale gear, wherein at least either the thickness of the gear is greater than 3 mm or the diameter of the gear is greater than 9 mm, comprising:
 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, wherein 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.   
     
     
         2 . The method of  claim 1 , wherein the obtained design parameters are based on the gear's anticipated operational setting. 
     
     
         3 . The method of  claim 2 , wherein the obtained design parameters include at least one of: the dimensions of the gear to be formed; the desired extent of the gear's resistance to brittle fracture; and the desired extent of the gear's resistance to standard modes of wear. 
     
     
         4 . The method of  claim 3 , wherein the obtained design parameters include the dimensions of the gear to be formed, the desired extent of the gear's resistance to brittle fracture, and the desired extent of the gear's resistance to standard modes of wear. 
     
     
         5 . The method of  claim 4 , wherein the extent of the gear's resistance to brittle fracture is determined based on its constituent material's fracture toughness. 
     
     
         6 . The method of  claim 5 , wherein the selected bulk metallic glass material is characterized by a fracture toughness of between approximately 20 MPa*m 1/2  and 80 MPa*m 1/2 . 
     
     
         7 . The method of  claim 6 , wherein the extent of a gear's resistance to standard modes of wear is determined based on its constituent material's hardness. 
     
     
         8 . The method of  claim 7 , wherein the selected bulk metallic glass material has a Vickers hardness value of at least 400. 
     
     
         9 . The method of  claim 4 , wherein the extent of the gear's resistance to standard modes of wear is determined based on its constituent material's performance in a pin-on-disk test. 
     
     
         10 . The method of  claim 4 , wherein the selected bulk metallic glass is an alloy based on one of: Zr, Ti, Cu, Pd, and Pt. 
     
     
         11 . The method of  claim 10 , wherein the selected bulk metallic glass is a TiZrBeX alloy, wherein X is a late transition metal. 
     
     
         12 . The method of  claim 11 , wherein:
 the atomic percentage of Ti is between approximately 30% and 60%;   the atomic percentage of Zr is between approximately 15% and 35%;   the atomic percentage of Be is between approximately 7% and 35%; and   the atomic percentage of the combination of all other constituent elements is less than approximately 20%.   
     
     
         13 . The method of  claim 11 , wherein:
 the selected bulk metallic glass is one of: Ti 45 Zr 16 Be 20 Cu 10 Ni 9 , Ti 30 Zr 35 Be 26.8 Cu 8.2 , and Ti 40 Zr 25 Be 30 Cr 5 .   
     
     
         14 . The method of  claim 3 , wherein the temperature of the environment at which the gear is anticipated to operate is below 0° C., and wherein the selected bulk metallic glass is characterized by a resistance to brittle failure at the anticipated operating temperature and under the corresponding anticipated operating conditions. 
     
     
         15 . The method of  claim 14 , wherein the obtained design parameters include a desired threshold resistance to brittle failure at the anticipated temperature that is determined by constituent material's Charpy impact energy at the anticipated temperature. 
     
     
         16 . The method of  claim 15 , wherein:
 the desired threshold Charpy impact energy at the anticipated temperature is correlated with a threshold Charpy impact energy at room temperature using a known relationship of Charpy impact energy as a function of temperature; and   selecting the bulk metallic glass based on its correlated threshold Charpy impact energy at room temperature.   
     
     
         17 . The method of  claim 16 , wherein the known relationship of Charpy impact energy as a function of temperature is linear. 
     
     
         18 . The method of  claim 17 , wherein the known relationship of Charpy impact energy as a function of temperature is 0.02 J/° C. 
     
     
         19 . The method of  claim 1 , wherein selecting a bulk metallic glass comprises:
 identifying an alloy system that is known to have a resistance to brittle failure that accords with the obtained design parameters; and   assessing micro-alloyed variants of the alloy system to select a particular composition that has a resistance to standard modes of wear as well as a resistance to brittle failure, from which a gear can be formed that accords with the obtained design parameters.   
     
     
         20 . A method of fabricating a bulk metallic glass-based macroscale gear, wherein at least either the thickness of the gear is greater than 3 mm or the diameter of the gear is greater than 9 mm, comprising:
 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, wherein the selected bulk metallic glass is characterized by a resistance to brittle failure 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.   
     
     
         21 . A bulk metallic glass-based macroscale gear, wherein at least either the thickness of the gear is greater than 3 mm or the diameter of the gear is greater than 9 mm, comprising a bulk metallic glass that is resistant to standard modes of wear and resistant to brittle failure. 
     
     
         22 . The bulk metallic glass-based macroscale gear of  claim 21 , wherein the fracture toughness of the bulk metal glass is between approximately 20 MPa*m 1/2  and 80 MPa*m 1/2 . 
     
     
         23 . The bulk metallic glass-based macroscale gear of  claim 22 , wherein the bulk metallic glass has a Vickers hardness value of at least 450. 
     
     
         24 . The bulk metallic glass-based macroscale gear of  claim 21 , wherein the bulk metallic glass is a TiZrBeX alloy, wherein X is a late transition metal. 
     
     
         25 . The bulk metallic glass of  claim 24 , wherein:
 the atomic percentage of Ti is between approximately 30% and 60%;   the atomic percentage of Zr is between approximately 15% and 35%;   the atomic percentage of Be is between approximately 7% and 35%; and   the atomic percentage of the combination of all other constituent elements is less than approximately 20%.   
     
     
         26 . The bulk metallic glass-based macroscale gear of  claim 24 , wherein the bulk metallic glass is one of: Ti 45 Zr 16 Be 20 Cu 10 Ni 9 , Ti 30 Zr 35 Be 26.8 Cu 8.2 , and Ti 40 Zr 25 Be 30 Cr 5 .