High-entropy alloy and method of heat-treating same

Abstract

A high-entropy alloy, according to the present embodiment, comprises a first phase and a second phase respectively comprising iron and copper, and iron and a first metal other than copper, and having mutually different compositions. A reinforcement compound formed by the chemical bonding of the first metal and a non-metal can be selectively included in the first phase.

1 . A high-entropy alloy comprising a first phase and a second phase respectively containing iron and copper, and iron and a first metal other than copper, and having different compositions,
 wherein a reinforcement compound formed by chemical bonding of the first metal and a non-metal is selectively included in the first phase.   
     
     
         2 . The high-entropy alloy of  claim 1 , wherein the reinforcement compound is formed as internal precipitates present within the first phase. 
     
     
         3 . The high-entropy alloy of  claim 1 , wherein the reinforcement compound comprises a first reinforcement precipitate formed near a surface of the first phase and having a first size, and a second reinforcement precipitate formed within the first phase and having a size larger than the first size. 
     
     
         4 . The high-entropy alloy of  claim 1 , wherein strength or hardness of the first phase is greater than strength or hardness of the second phase, and the reinforcement compound is not formed in the second phase. 
     
     
         5 . The high-entropy alloy of  claim 4 , wherein the hardness of the first phase is twice or greater than the hardness of the second phase. 
     
     
         6 . The high-entropy alloy of  claim 1 , wherein the first phase is a Fe-rich phase, and the second phase is a Cu-rich phase. 
     
     
         7 . The high-entropy alloy of  claim 1 , wherein the first metal comprises aluminum. 
     
     
         8 . The high-entropy alloy of  claim 1 , wherein the non-metal has a higher solubility in the first phase than in the second phase, and has a higher diffusion rate in the first phase than in the second phase. 
     
     
         9 . The high-entropy alloy of  claim 1 , wherein the non-metal comprises nitrogen or oxygen. 
     
     
         10 . The high-entropy alloy of  claim 1 , wherein the reinforcement compound comprises aluminum nitride (AlN). 
     
     
         11 . A method of heat-treating a high-entropy alloy, the method comprising:
 a preparation step of preparing a high-entropy alloy material comprising a first phase and a second phase respectively containing iron and copper, and iron and a first metal other than copper, and having different compositions; and   a selective reinforcement step of forming a reinforcement compound in the first phase by performing heat-treatment using a non-metal for a chemical reaction between the first metal, contained in the first phase, and the non-metal.   
     
     
         12 . The method of  claim 11 , wherein the first metal comprises aluminum. 
     
     
         13 . The method of  claim 11 , wherein the non-metal has a higher solubility in the first phase than in the second phase, and has a higher diffusion rate in the first phase than in the second phase. 
     
     
         14 . The method of  claim 11 , wherein the non-metal comprises nitrogen or oxygen, such that the selective reinforcement step is carried out by nitriding treatment or oxidation treatment. 
     
     
         15 . The method of  claim 11 , wherein the selective reinforcement step is carried out at a heat treatment temperature of 500° C. to 1500° C. 
     
     
         16 . The method of  claim 11 , wherein the selective reinforcement step is carried out by nitriding treatment using a reactive gas containing an ammonia gas and a hydrogen gas, and the first metal comprising aluminum such that the reinforcement compound comprises aluminum nitride (AlN). 
     
     
         17 . The method of  claim 16 , wherein the hydrogen gas is contained in an amount of 10 vol% or less based on a total of 100 vol% of the reactive gas. 
     
     
         18 . The method of  claim 11 , wherein the first phase is a Fe-rich phase, and the second phase is a Cu-rich phase. 
     
     
         19 . The method of  claim 11 , wherein the reinforcement compound is formed as internal precipitates present within the first phase. 
     
     
         20 . The method of  claim 11 , wherein strength or hardness of the first phase is greater than strength or hardness of the second phase, and the reinforcement compound is not formed in the second phase.