Postech Academy-industry Foundation

The Industry & Academic Cooperation in Chungnam National University

Agency for Defense Development

Hyoung-seop Kim

Sung-hak Lee

Byeong-joo Lee

Won-mi Choi

Sun-ig Hong

Chang-woo Jeon

Seung-mun Jung

Young-sang Na

Seong Min Lee

Dong-geun Kim

Seong-Ho Yang

Seok-su Sohn

Ho-Yong Um

Yong-hee Jo

Lee-Ju Park

Hak-Jun Kim

See-Am Lee

Present invention is about a transformation-induced plasticity high-entropy alloy which can provide improved mechanical properties compared to those obtained by conventional methods, due to the phase transformation occurring at the time of deformation at a cryogenic temperature. According to the present invention, the high-entropy alloy (HEA) includes 10-35 at % of Co, 3-15 at % of Cr, 3-15 at % of V, 35-48 at % of Fe, and 0-25 at % of Ni (exclusive of 25), and mainly consists of an FCC phase at room temperature, wherein transformation-induced plasticity, in which at least part of the FCC phase changes to a BCC phase, occurs at a cryogenic temperature (&#x2212;196&#xb0; C.)

Transformation-induced plasticity high-entropy alloy and preparation method thereof

The present invention relates to a high-entropy alloy especially having excellent low-temperature tensile strength and elongation by means of having configured, through thermodynamic calculations, an alloy composition region having an FCC single-phase microstructure at 700&#xb0; C. or higher, and enabling the FCC single-phase microstructure at room temperature and at an ultra-low temperature. The high-entropy alloy, according to the present invention, comprises: Co: 3-12 at %; Cr: 3-18 at %; Fe: 3-50 at %; Mn: 3-20 at %; Ni: 17-45 at %; V: 3-12 at %; and unavoidable impurities, wherein the ratio of the V content to the Ni content (V/Ni) is 0.5 or less, and the sum of the V content and the Co content is 22 at % or less.

High-entropy alloy for ultra-low temperature

The present invention relates to a high-entropy alloy especially having excellent low-temperature tensile strength and elongation by means of having configured, through thermodynamic calculations, an alloy composition region having an FCC single-phase microstructure at 700&#xb0; C. or higher, and enabling the FCC single-phase microstructure at room temperature and at an ultra-low temperature. The high-entropy alloy, according to the present invention, comprises: Cr: 3-18 at %; Fe: 3-60 at %; Mn: 3-40 at% ; Ni: 20-80 at %: 3-12 at %; and unavoidable impurities, wherein the ratio of the V content to the Ni content (V/Ni) is 0.5 or less.

Cr&#x2014;Fe&#x2014;Mn&#x2014;Ni&#x2014;V-based high-entropy alloy

In a localized torsional severe plastic deformation method for conical tube metal, a desired region of a conical tube metal can be subjected to severe plastic deformation using molds in which roughness is formed at predetermined regions. The method includes roughening a predetermined region of each of the molds; sticking the conical tube metal only to the roughened regions of the molds; moving the lower mold toward the upper mold to apply a load to the conical tube metal; and rotating the molds to apply severe plastic deformation to the conical tube metal only at the regions stuck to the roughened regions of the molds.

Localized torsional severe plastic deformation method for conical tube metals

Growing community of inventors

Pohang-si, South Korea

Hyoung-seop Kim