Method of forming cellular material

Abstract

Systems, devices and methods are provided that are related to cellular materials that have a precisely-determined arrangement of voids formed using surface transformation. In various embodiments, the cellular materials are suitable for use in various structural, mechanical and/or thermal applications. One aspect of the present subject matter is a method of forming cellular material. According to various embodiments of the method, a predetermined arrangement of the plurality of holes is formed in a volume of material through a surface of the volume of material. The volume of material is annealed such that the volume of material undergoes a surface transformation in which the arrangement of the plurality of holes is transformed into a predetermined arrangement of at least one empty space below the surface of the volume of material. Other aspects are provided herein.

1 . A structure of cellular material, comprising:
 a solid structure of material having a well-defined melting temperature and a well-defined annealing temperature below the melting temperature suitable to perform a surface transformation process; and   a precisely-determined arrangement of a plurality of voids formed within the solid structure, the plurality of voids being separated by a critical length (?C) that is dependent on the radius (RC) of a number of holes used to form the plurality of voids using the surface transformation process,   wherein a majority of the precisely-determined arrangement of the plurality of voids within the solid structure are closed and approximately uniformly spaced to provide the structure of cellular material with a uniform density.   
     
     
         2 . The structure of  claim 1 , wherein the precisely-determined arrangement of the plurality of voids includes at least one surface transformation formed empty space. 
     
     
         3 . The structure of  claim 2 , wherein the structure of cellular material with at least one surface transformation formed empty space is formed using the surface transformation process to provide the structure with the uniform density, wherein performing the surface transformation process includes:
 determining a desired arrangement for a plurality of holes through a surface of a volume of material, wherein the desired arrangement for the plurality of holes includes a location, diameter and depth for each of the plurality of holes control the size and location for each of the at least one empty space that results from the surface transformation process;   forming the arrangement of the plurality of holes in the volume of material through the surface of the volume of material; and   annealing the volume of material such that the volume of material undergoes a surface transformation to transform the arrangement of the plurality of holes into the arrangement of at least one empty space below the surface of the volume of material to provide the material with the uniform density.   
     
     
         4 . The structure of  claim 1 , wherein the precisely-determined arrangement of the plurality of voids within the solid structure are approximately uniformly spaced and are closed voids such that a relationship between stiffness (S) and density (?) for the structure of cellular material approaches S a ?−2. 
     
     
         5 . The structure of  claim 1 , wherein the precisely-determined arrangement of the plurality of voids includes a plate-shaped void. 
     
     
         6 . The structure of  claim 5 , wherein the precisely-determined arrangement of the plurality of voids includes at least one stack of plate-shaped voids. 
     
     
         7 . The structure of  claim 1 , wherein the precisely-determined arrangement of the plurality of voids includes at least one pipe-shaped void. 
     
     
         8 . The structure of  claim 7 , wherein the precisely-determined arrangement of the plurality of voids includes at least one stack of pipe-shaped voids. 
     
     
         9 . The structure of  claim 1 , wherein the precisely-determined arrangement of the plurality of voids includes at least one sphere-shaped void. 
     
     
         10 . The structure of  claim 9 , wherein the precisely-determined arrangement of the plurality of voids includes at least one stack of sphere-shaped voids. 
     
     
         11 . The structure of  claim 1 , wherein the precisely-determined arrangement of the plurality of voids includes a combination of at least two arrangements of:
 a precisely-determined arrangement of at least one empty sphere;   a precisely-determined arrangement of at least one empty pipe; and   a precisely-determined arrangement of at least one empty plate.   
     
     
         12 . A structure of cellular material, comprising:
 a solid structure of material having a well-defined melting temperature and a well-defined annealing temperature below the melting temperature suitable to perform a surface transformation process; and   a precisely-determined arrangement of a plurality of voids formed within the solid structure, the plurality of voids being separated by a critical length (?C) that is dependent on the radius (RC) of a number of holes used to form the plurality of voids using the surface transformation process,   wherein the precisely-determined arrangement of the plurality of voids within the solid structure are arranged to provide the structure with a predictable mechanical failure for a given force.   
     
     
         13 . The structure of  claim 12 , wherein the precisely-determined arrangement of the plurality of voids includes at least one plate-shaped void. 
     
     
         14 . The structure of  claim 12 , wherein the precisely-determined arrangement of the plurality of voids includes at least one pipe-shaped void. 
     
     
         15 . The structure of  claim 12 , wherein the precisely-determined arrangement of a plurality of voids includes at least one sphere-shaped void. 
     
     
         16 . The structure of  claim 12 , wherein the precisely-determined arrangement of the plurality of voids includes a combination of at least two arrangements of:
 a precisely-determined arrangement of at least one empty sphere;   a precisely-determined arrangement of at least one empty pipe; and   a precisely-determined arrangement of at least one empty plate.   
     
     
         17 . The structure of  claim 12 , wherein the structure of cellular material is incorporated in a system, and the precisely-determined arrangement of the plurality of voids within the solid structure are arranged to provide the structure with a predictable mechanical failure to predictably absorb energy from a crash. 
     
     
         18 . The structure of  claim 12 , wherein:
 the structure of cellular material is incorporated in a system having easily replaceable components and other components; and   the precisely-determined arrangement of the plurality of voids within the solid structure are arranged to provide the structure with a predictable mechanical failure to predictably break the easily replaceable component.   
     
     
         19 . The structure of  claim 12 , wherein the plurality of voids includes a first set of voids of a first size and a second set of voids of a second size. 
     
     
         20 . The structure of  claim 19 , wherein the voids in the first set are interposed among the voids in the second set. 
     
     
         21 . The structure of  claim 12 , wherein the structure of cellular material with at least one surface transformation formed empty space is formed by the surface transformation process to provide the structure with the predictable mechanical failure, wherein the surface transformation process includes:
 determining a desired arrangement for a plurality of holes through a surface of a volume of material, wherein the desired arrangement for the plurality of holes includes a location, diameter and depth for each of the plurality of holes control the size and location for each of the at least one empty space that results from the surface transformation process;   forming the arrangement of the plurality of holes in the volume of material through the surface of the volume of material; and   annealing the volume of material such that the volume of material undergoes a surface transformation to transform the arrangement of the plurality of holes into the arrangement of at least one empty space below the surface of the volume of material to provide the material with the predictable mechanical failure.