Twinning/transformation induced plasticity high entropy steels and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-2020056272-A1
Application number	US-201916507474-A
Country	US
Kind code	A1
Filing date	Jul 10, 2019
Priority date	Aug 14, 2018
Publication date	Feb 20, 2020
Grant date	—

Abstract

A high entropy steel in which twinning and phase transformation are simultaneously performed, and a method of manufacturing the same, are provided. The high entropy steel includes three or more alloying elements selected from the following, by atomic percentage: iron (Fe) from 35% to 80%, nickel (Ni) from 5% to 35%, manganese (Mn) from 5% to 35%, cobalt (Co) from 5% to 35%, and chromium (Cr) from 5% to 35%

First claim

What is claimed is:

1 . A high entropy steel having excellent workability and hardening performance, comprising:
three or more alloying elements selected from the following, by atomic percentage: iron (Fe) from 35% to 80%, nickel (Ni) from 5% to 35%, manganese (Mn) from 5% to 35%, cobalt (Co) from 5% to 35%, and chromium (Cr) from 5% to 35.

2 . The high entropy steel of claim 1 , further comprising, by atomic %, one or more selected from carbon (C) from 0.01% to 5.0%, nitrogen (N) from 0.01% to 5.0%, boron (B) from 0.01% to 5.0%, silicon (Si) from 0.01% to 10%, copper (Cu) from 0.01% to 10%, vanadium (V) from 0.01% to 10%, and aluminum (Al) from 0.01% to 10%.

3 . The high entropy steel of claim 1 , wherein stacking fault energy is 40 mJ/m 2 or less, and ‘an atomic size difference x an alloy composition % value’ is 0.05 or more.

4 . A method of manufacturing a high entropy steel having excellent workability and work hardening performance, the method comprising:
preparing a metallic material including an three or more alloying elements selected from the following, by atomic percentage: iron (Fe) from 35% to 80%, nickel (Ni) from 5% to 35%, manganese (Mn) from 5% to 35%, cobalt (Co) from 5% to 35%, and chromium (Cr) from 5% to 35; producing the prepared metallic material as molten alloy; applying a homogenizing heat treatment on the alloy in the temperature range between 850° C. and 1250° C., and then cooling the alloy in the room temperature; and after processing the cooled alloy, applying a second heat treatment where the alloy is maintained in the temperature range between 350° C. and 850° C. for 0.5 to 72 hours.

5 . The method of claim 4 , wherein the high entropy steel further comprises, by atomic %, one or more selected from carbon (C) from 0.01% to 5.0%, nitrogen (N) from 0.01% to 5.0%, boron (B) from 0.01% to 5.0%, silicon (Si) from 0.01% to 10%, copper (Cu) from 0.01% to 10%, vanadium (V) from 0.01% to 10%, and aluminum (Al) from 0.01% to 10

6 . The method of claim 4 , wherein the metallic material is produced as a molten alloy, using one method selected from casting, arc melting, powder metallurgy, thermal spray casting, thermal spray coating, spray coating, and 3D-printing.

7 . The method of claim 4 , wherein the processing of the cooled alloy is performed using one of forging, extrusion, rolling and drawing.

Assignees

• Iac In Nat Univ Chungnam

Inventors

• Hong Sun Ig
• Song Jae Sook
• Lee Byung Ju

Classifications

• C22C38/16

  containing copper · CPC title

• C22C38/02

  containing silicon · CPC title

• C22C38/24

  with vanadium · CPC title

• C22C38/105

  containing Co and Ni · CPC title

• C22C38/001

  containing N · CPC title