High-entropy alloy foam and manufacturing method for the foam

Abstract

The present invention relates to a HEA foam prepared by selective dissolution of a second phase within a two-phase separating alloy comprising the HEA and a manufacturing method thereof. The manufacturing method of the HEA foam of the present invention has the effect of preparing a novel HEA foam, which was not available in the past, by leaving only a first phase after manufacturing a two-phase separating alloy comprising a first phase by HEA, wherein at least 3 metal elements act as a common solvent. Furthermore, the HEA foam of the present invention has a structure, wherein pores are distributed inside the HEA, in which at least 3 metal elements act as a common solvent. By adding a functional characteristic of low heat conductivity, etc., to the existing high strength characteristic of HEA, the HEA foam of the present invention can exhibit a complex effect by the combination of the two particular effects, thereby being capable of exhibiting excellent physical characteristics.

What is claimed is: 
     
         1 . A two-phase separating alloy, comprising:
 a first phase comprising a high-entropy alloy (HEA) material, in which at least 3 metal elements act as a common solvent; and   a second phase comprising at least one metal element (M).   
     
     
         2 . The two-phase separating alloy of  claim 1 , wherein:
 all metal elements comprised in the high-entropy alloy (HEA) material on the first phase have an equiatomic ratio within an error range of 10 at. %.   
     
     
         3 . The two-phase separating alloy of  claim 1 , wherein:
 the first phase has a dendritic structure and the second phase is located in interdendritic regions.   
     
     
         4 . The two-phase separating alloy of  claim 1 , wherein:
 the high-entropy alloy (HEA) material on the first phase comprises at least 3 metal elements among Cr, Mn, Fe, Co, and Ni;   the high-entropy alloy (HEA) material has a face-centered cubic crystal structure; and   the metal element material (M) on the second phase comprises at least one metal element among Cu, Ag, and Au.   
     
     
         5 . The two-phase separating alloy of  claim 4 , wherein:
 the high-entropy alloy (HEA) material and the metal element material (M) are represented by a composition ratio of M 100-x (HEA) x  (with the proviso, 5≦x≦90 at. %).   
     
     
         6 . The two-phase separating alloy of  claim 4 , wherein:
 the high-entropy alloy (HEA) material further comprises at least one metal element among Ti, V, and Al; and   at least one metal element among Ti, V, and Al, is comprised 15 at. % or less relative to the high-entropy alloy (HEA) material.   
     
     
         7 . The two-phase separating alloy of  claim 4 , wherein:
 the high-entropy alloy (HEA) material further comprises at least one metal element among B, Si, Y, Zr, Nb, Mo, Ta, W, and Bi; and   at least one element among B, Si, Y, Zr, Nb, Mo, Ta, W, and Bi is comprised 10 at. % or less relative to the high-entropy alloy (HEA) material.   
     
     
         8 . The two-phase separating alloy of  claim 1 , wherein:
 the high-entropy alloy (HEA) material on the first phase comprises at least one metal element among Ti, V, and Cr, and at least one metal element among Zr, Nb, Mo, Hf, Ta, and W;   the high-entropy alloy (HEA) material has a body-centered cubic crystal structure; and   the metal element material (M) on the second phase comprises at least one metal element among Y, La, Ce, Nd, Gd, Tb, Dy, Ho, and Er.   
     
     
         9 . The two-phase separating alloy of  claim 8 , wherein:
 the high-entropy alloy (HEA) material and the metal element material (M) are represented by a composition ratio of M 100-x (HEA) x  (with the proviso, 1≦x≦25 at. %).   
     
     
         10 . The two-phase separating alloy of  claim 8 , wherein:
 the high-entropy alloy (HEA) material further comprises at least one metal element among B, C, N, Al, and Si; and   at least one element among B, C, N, Al, and Si is comprised 10 at. % or less relative to the high-entropy alloy (HEA) material.   
     
     
         11 . A manufacturing method of a HEA foam, comprising:
 a step for preparing a raw material for preparing at least 3 metal elements that constitute a high-entropy alloy (HEA) material and at least one metal element material (M) having a positive (+) heat of mixing relationship with at least 3 metal elements that constitute the high-entropy alloy (HEA) material;   a step for preparing an alloy for preparing a two-phase separating alloy, wherein a first phase comprising the high-entropy alloy (HEA) material and a second phase comprising at least one metal element (M) are separated from each other, by dissolving all the metal elements comprised in the step for preparing an alloy followed by cooling; and   a step for selectively removing only the second phase and forming pores.   
     
     
         12 . The manufacturing method of  claim 11 , wherein:
 in the step for preparing the alloy, the first phase has a dendritic structure and the second phase is located in interdendritic regions; and   in the step for preparing pores, the second phase is removed from the two-phase separating alloy and thus pores, which are located in the interdendritic regions, are formed.   
     
     
         13 . The manufacturing method of  claim 11 , wherein:
 in the step for preparing pores, the second phase is removed through an electrochemical dealloying process using nitric acid.   
     
     
         14 . HEA foam comprising a high-entropy alloy (HEA) material, in which at least 3 metal elements act as a common solvent, and pores located therein. 
     
     
         15 . The HEA foam of  claim 14 , wherein:
 the HEA foam has a dendritic structure.   
     
     
         16 . The HEA foam of  claim 14 , wherein:
 the high-entropy alloy (HEA) material comprises at least 3 metal elements among Cr, Mn, Fe, Co, and Ni; and   the high-entropy alloy (HEA) material has a face-centered cubic crystal structure.   
     
     
         17 . The HEA foam of  claim 16 , wherein:
 the high-entropy alloy (HEA) material further comprises at least one metal element among Ti, V, and Al; and   at least one metal element among Ti, V, and Al, is comprised 15 at. % or less relative to the high-entropy alloy (HEA) material.   
     
     
         18 . The HEA foam of  claim 16 , wherein:
 the high-entropy alloy (HEA) material further comprises at least one metal element among B, Si, Y, Zr, Nb, Mo, Ta, W, and Bi; and   at least one element among B, Si, Y, Zr, Nb, Mo, Ta, W, and Bi is comprised 10 at. % or less relative to the high-entropy alloy (HEA) material.   
     
     
         19 . The HEA foam of  claim 14 , wherein:
 the high-entropy alloy (HEA) material comprises at least one metal element among Ti, V, and Al; and at least one metal element among Zr, Nb, Mo, Hf, Ta, and W; and   the high-entropy alloy (HEA) material has a body-centered cubic crystal structure.   
     
     
         20 . The HEA foam of  claim 19 , wherein:
 the high-entropy alloy (HEA) material further comprises at least one metal element among B, C, N, Al, and Si; and   at least one element among B, C, N, Al, and Si is comprised 10 at. % or less relative to the high-entropy alloy (HEA) material.