High entropy alloy doped with boron and method for manufacturing the same

Abstract

The present invention introduces a high entropy alloy doped with boron, comprising four or more metals selected from iron (Fe), chromium (Cr), nickel (Ni), cobalt (Co), manganese (Mn), molybdenum (Mo), aluminum (Al) and copper (Cu), and boron (B) which has single phase FCC structure.

1 . A high entropy alloy doped with boron, comprising:
 four or more metals selected from iron (Fe), chromium (Cr), nickel (Ni), cobalt (Co), manganese (Mn), molybdenum (Mo), aluminum (Al) and copper (Cu), and boron (B) and   having single phase FCC structure.   
     
     
         2 . The high entropy alloy doped with boron of  claim 1 , wherein the content of the four or more metals is 5 to 35 at % respectively, and the content of boron (B) is 3 at % or less (0 is not included). 
     
     
         3 . The high entropy alloy doped with boron of  claim 1 , wherein the alloy comprises 18 to 42% of iron (Fe), 18 to 42% of manganese (Mn), 9 to 22% of chromium (Cr), 9 to 22% of cobalt (Co), 9 to 22% of nickel (Ni) and 0.001 to 0.01% of boron (B) on the basis of weight %. 
     
     
         4 . The high entropy alloy doped with boron of  claim 1 , wherein the alloy comprises 18 to 42% of iron (Fe), 18 to 42% of manganese (Mn), 9 to 22% of chromium (Cr), 9 to 22% of cobalt (Co) and 0.001 to 0.01% of boron (B) on the basis of weight %. 
     
     
         5 . The high entropy alloy doped with boron of  claim 3 , wherein the alloy comprises 0.004 to 0.005% of boron (B). 
     
     
         6 . The high entropy alloy doped with boron of  claim 1 , wherein the alloy comprises boron (B) segregated in grain boundary. 
     
     
         7 . The high entropy alloy doped with boron of  claim 6 , wherein the maximum concentration of the boron (B) segregated in the grain boundary is 0.20 at %. 
     
     
         8 . The high entropy alloy doped with boron of  claim 6 , wherein the boron (B) segregated in the grain boundary is 95% or more of the total boron (B). 
     
     
         9 . The high entropy alloy doped with boron of  claim 1 , wherein the average grain size of the alloy is 60 μm or less. 
     
     
         10 . The high entropy alloy doped with boron of  claim 1 , wherein the yield strength of the alloy is 450 MPa or more. 
     
     
         11 . A method for manufacturing a high entropy alloy doped with boron, comprising:
 preparing a raw material of four or more metals selected from iron (Fe), chromium (Cr), nickel (Ni), cobalt (Co), manganese (Mn), molybdenum (Mo), aluminum (Al) and copper (Cu), and a raw material of boron (B);   dissolving the raw materials to cast an ingot;   cold-rolling the ingot to produce an alloy material; and   annealing the alloy material;   wherein the alloy material has a single phase FCC structure.   
     
     
         12 . The method of  claim 11 , further comprising:
 homogenizing heat treating the ingot; and   removing oxides generated on the surface of the ingot; after the step of casting the ingot.   
     
     
         13 . The method of  claim 11 , wherein in the step of annealing the alloy material, the annealing temperature is 650 to 1100° C. 
     
     
         14 . The method of  claim 11 , further comprising:
 forming mechanical twinned crystal by deformation of the alloy material;   after the step of annealing the alloy material.   
     
     
         15 . The high entropy alloy doped with boron of  claim 4 , wherein the alloy comprises 0.004 to 0.005% of boron (B).