서지주요정보
Fabrication and characterization of high-strength refractory AlMo$_{0.5}$NbTa$_{0.5}$TiZr and AlMo$_{0.5}$Nb(TaW)$_{0.5}$TiZr High Entropy Alloy = AlMo$_{0.5}$NbTa$_{0.5}$TiZr 및 AlMo$_{0.5}$Nb(TaW)$_{0.5}$TiZr 내열 하이엔트로피 합금의 제조공정 및 특성 연구
서명 / 저자 Fabrication and characterization of high-strength refractory AlMo$_{0.5}$NbTa$_{0.5}$TiZr and AlMo$_{0.5}$Nb(TaW)$_{0.5}$TiZr High Entropy Alloy = AlMo$_{0.5}$NbTa$_{0.5}$TiZr 및 AlMo$_{0.5}$Nb(TaW)$_{0.5}$TiZr 내열 하이엔트로피 합금의 제조공정 및 특성 연구 / Yuqiao Li.
저자명 Li, Yuqiao
발행사항 [대전 : 한국과학기술원, 2017].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8031371

소장위치/청구기호

학술문화관(문화관) 보존서고

MMS 17053

SMS전송

도서상태

이용가능

대출가능

반납예정일

초록정보

Different from conventional alloys composed of one main element with addition of minor elements, High Entropy Alloys (HEAs) consist of 5-13 metallic elements with equi- or near equi-atomic ratio. Due to the characteristics of the high entropy alloys: High mixing entropy, severe lattice distortion because of atomic size difference, sluggish diffusion rate, and cocktail effect, HEAs exhibit excellent mechanical properties and attract a wide spread attention. Therefore, a variety of the research of new HEA systems have been conducted. The fabricate process of refractory HEAs is mainly focused on arc-melting and casting process which has following problems: inhomogeneous microstructure because of segregation of alloy elements, grain coarsening during the cooling. In this study, powder metallurgical process (PM) was applied to fabricate the refractory HEAs to homogenize the microstructure and enhance the mechanical properties. Here, two refractory HEA system of AlMo$_{0.5}$NbTa$_{0.5}$TiZr and AlMo$_{0.5}$Nb(TaW)$_{0.5}$TiZr was produced and characterized. AlMo$_(0.5)$NbTa$_(0.5)$TiZr HEA is known for its excellent mechanical property at room temperature, low density, but low elongation at room temperature, low strength at temperature higher than 1000$^\circ C$ with expensive cost of raw materials. To reduce the contaminations during the mechanical alloying, minimum time of mechanical alloying was conducted. HEA bulks were prepared by spark plasma sintering. Different sintering temperatures were employed to compare the properties. The mechanical properties of fabricated bulk specimen were evaluated by Vickers hardness test and compressive test. Consequently, it was obvious that the HEAs fabricated by powder metallurgical process exhibit enhanced mechanical properties than those of arc-melting and casting process. Addition of W effectively improved mechanical properties at elevated temperature. Based on this study of fabricating refractory HEAs by powder metallurgical process, it is expected to develop further research to find new refractory high entropy alloys and improve the mechanical properties by grain growth.

본 연구에서는, 내열 하이엔트로피 합금의 제조법으로써 합금의 미세조직 균일화 및 기계적특성을 향상을 목적으로 분말공정을 적용하였다. AlMo$_{0.5}$NbTa$_{0.5}$TiZr및 AlMo$_{0.5}$Nb(TaW)$_{0.5}$TiZr 두 조성의 내열 하이엔트로피 합금의 제조법과 특성평가를 진행하였다.

서지기타정보

서지기타정보
청구기호 {MMS 17053
형태사항 vi, 80 p. : 삽도 ; 30 cm
언어 영어
일반주기 지도교수의 영문표기 : Soon Hyung Hong
지도교수의 한글표기 : 홍순형
학위논문 학위논문(석사) - 한국과학기술원 : 신소재공학과,
서지주기 References: p. 76-78
주제 High entropy alloy
Powder metallurgical process
Compression strength
Refractory alloys
Hardness
Grain boundary strengthening
하이엔트로피합금
분말공정
압축강도
내열합금
경도
결정립계 강화
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