High-entropy alloy foam and manufacturing method for the foam

Patent metadata

Field	Value
Publication number	US-10941463-B2
Application number	US-202016743031-A
Country	US
Kind code	B2
Filing date	Jan 15, 2020
Priority date	Jan 29, 2016
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

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.

First claim

What is claimed is:

1. A method of manufacturing a high-entropy alloy foam of M 100-x (HEA) x (5≤x≤90), the method comprising:
preparing a raw material comprising:
a high-entropy alloy with a face-centered cubic crystal structure comprising:
Mn; and
at least two metal elements selected from a group of Cr, Fe, Co, and Ni; and

at least one additive metal element selected from a group of Cu, Ag and Au of 10 at % or less relative to the high-entropy alloy, the additive metal element having a positive heat of mixing relationship with the high-entropy alloy; and

dissolving and cooling an alloy comprising:
a first phase comprising the high-entropy alloy; and
a second phase comprising the at least one additive metal element, the second phase separated from the first phase; and

selectively removing the second phase by electrochemical dealloying and then forming pores; and wherein
the M represents the additive metal element and the HEA represents the high-entropy alloy.

2. The method of claim 1 , wherein in the selectively removing the second phase, the electrochemical dealloying is performed by promoting galvani battery reaction by dipping the alloy into nitric acid solution.

3. The method of claim 1 , wherein the high-entropy alloy further comprises at least one metal element among Ti, V, and Al of 15 at % or less of the high-entropy alloy in the preparing a raw material.

4. The manufacturing method of claim 1 , wherein in the preparing a raw material, the high-entropy alloy further comprises at least one metal element among B, Si, Y, Zr, Nb, Mo, Ta, W and Bi of 10 at % or less of the high-entropy alloy.

5. The method of claim 1 , wherein the first phase has a dendritic structure and the second phase is located in interdendritic regions in the dissolving and cooling an alloy; and wherein
the second phase is removed from the alloy and thus the pores are located in the interdendritic regions in the selectively removing the second phase.

6. The method of claim 1 , wherein the alloy is solidified with monotectic reaction in the cooling an alloy.

7. The method of claim 1 , wherein the second phase is over 50 vol % in the dissolving and cooling an alloy, the method further comprises sintering the alloy from which the second phase is selectively removed.

8. A method of manufacturing a high-entropy alloy foam of M 100-x (HEA) x (1≤x≤25), the method comprising:
preparing a raw material comprising:
a high-entropy alloy with a body-centered cubic crystal structure comprising:
at least one metal element selected from a group of Ti, V, and Cr; and
at least one metal element selected from a group of Zr, Nb, Mo, Hf, Ta and W; and

at least one additive metal element selected from a group of Y, La, Ce, Nd, Gd, Tb, Dy, Ho, and Er having a positive heat of mixing relationship with the high-entropy alloy; and

dissolving and cooling an alloy comprising:
a first phase comprising the high-entropy alloy; and
a second phase comprising the at least one additive metal element, the second phase separated from the first phase; and

selectively removing the second phase by electrochemical dealloying and then forming pores; and wherein
the M represents the additive metal element and the HEA represents the high-entropy alloy.

9. The method of claim 8 , wherein in the selectively removing the second phase, the electrochemical dealloying is performed by promoting galvani battery reaction by dipping the alloy into nitric acid solution.

10. The method of claim 8 , wherein the alloy is solidified with monotectic reaction in the cooling an alloy.

11. The method of claim 8 , wherein the high-entropy alloy further comprises at least one metal element among B, C, N, Al and Si of 10 at % or less of the high-entropy alloy in the preparing a raw material.

12. The method of claim 1 , wherein the first phase has a dendritic structure and the second phase is located in interdendritic regions in the dissolving and cooling an alloy; and wherein
the second phase is removed from the alloy and thus the pores are located in the interdendritic regions in the selectively removing the second phase.

13. The method of claim 8 , wherein the second phase is over 50 vol % in the dissolving and cooling an alloy, the method further comprises sintering the alloy from which the second phase is selectively removed.

Assignees

• Seoul Nat Univ R&Db Foundation

Inventors

• Park Eun Soo
• Yoon Kooknoh
• Yaqoob Khurram
• Lee Je In
• Kim Jin Yeon

Classifications

• C22C3/005

  Separation of the constituents of alloys · CPC title

• B22D25/005

  Casting metal foams · CPC title

• B22F3/10

  Sintering only · CPC title

• C23F1/26

  for etching refractory metals · CPC title

• C23F1/30

  for etching other metallic material · CPC title